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Stats Real 1 Flashcards

1
Q 
1. When computing the variance of a sample, the sum of the squared deviations, E (x-x)z, is divided by?
A. The population size
B. The sample size minus one
C. The sample size
D. The population size minus one
E. None of the above
A

B

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2
Q 
2. A company wants to graphically summarize in one chart the number of employees it has in each of its five decisions.  What type of chart would be appropriate for this purpose? (On the test)
A. Line chart 
B. Box plot 
C. Scatter diagram 
D. Bar chart
E. None of the above
A

D

Bar chart because it’s qualititave. Each employee

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3
Q 
3. A manufacturer claims to have built a home stereo speaker that is 4 feet tall but uses an average of only 30 watts of power.  A sample of 40 speakers from the manufacturer found that they used an average of 32 watts of power.  The appropriate hypotheses to test the manufacturer’s claim are?
A. Ho: M=30 versus HA:M=not equal30
B. Ho: M=32 versus HA: M=not equal32
C. Ho: M=30 versus HA:M=32
D. Ho: M=30 versus HA:M>30
E. None of the above
A

D

Built a home 4 ft tall but uses 30 watts

40 speakers used 32 watts

Ming Notes:
Original claim: Ho: M = 30
Alternate claim: Ha: M > 30. (test whether the alternate occurred by accident).
D.

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4
Q
  1. If the alternative hypothesis states that the population mean is not equal to 3500, the rejection region will consist of?
    A. One region in the left tail (below 3500)
    B. One region in the right tail (above 3500)
    C. Two regions, one in the right tail and one in the left tail.
    D. One region, centered about 3500.
    E. None of the above.
A

C

Problem states “not equal” so that means two regions.

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5
Q
  1. A 98% confidence interval for a population proportion is determined to be 0.756 to 0.834. If the confidence level is reduced to 95%, the same data will produce an interval that?
    A. Is wider
    B. Is narrower
    C. Is the same
    D. You cannot answer the questions without knowing the sample size.
    E. None of the above.
A

B

98% to 95% is narrower

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6
Q
  1. If the correlation coefficient, r, is equal to one?
    A. The y-intercept must be equal to zero
    B. The regression line goes through all the points and has a negative slope.
    C. The standard error of the estimate, Sz is zero.
    D. The slope of the regression line is one.
    E. None of the above.
A

C

If r is =1 then Sz=0

Slide 63

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7
Q 
7. The expected value of a random variable is also?
A. The median.
B. The mode
C. A weighted average 
D. The variance
E. None of the above
A

C

Expected value is a weighted average, also a long-run average. Slide 78

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8
Q 
8. A study if elementary schools in the Los Angeles Unified School District focused on the percentage of teachers in each school with emergency credentials (x, in percent) and the average reading scores (y) of fourth grade students in that school.  The least squares regression line was y=400-3x.  If twenty percent of the teachers in prairie Elementary in the San Fernando Valley have emergency credentials, you would expect the average reading scores of the fourth grade students in prairie Elementary to be? (On the test)
A. 60
B. 100
C. 340
D. 399.4
E. None of the above
A

C

400-3(20)
=400-60=340

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9
Q 
9. Ten percent of the mail that arrives at a post office has insufficient postage attached.  If a postal worker selects 15 pieces of mail at random, what probability distribution should he use to calculate the probability that three pieces of mail have sufficient postage?
A. Poisson
B. Exponential 
C. Normal 
D. Uniform
E. None of the above
A 
E
There are 3 types of Distribution
T Distribution ( Mean) 
Binomial
Normal
Sampling

Poisson, Exponential, Uniform does not exist. Therefore it can either be Normal or None of the Above. However Normal is

Continuous, bell-shaped, symmetric
Mean=median=mode
Measurement (dollars, inches, years)
Cumulative probability under normal curve : use Z table if you know population mean and population standard deviation
Sample mean: use Z table if you know population standard deviation and either normal population or n > 30

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10
Q 
10. If the population is normal, the population standard deviation is known, and the sample size is ten, which table would you use for calculating probability of the sample mean?
A. Normal 
B. Student t
C. Chi-square
D. Binomial
E. None of the above
A

A

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11
Q
  1. If the null hypothesis is that the population mean is equal to 30 and you conduct a test with a significance level of 0.05 and get a p-value of 0.08, then?
    A. You must reject the null hypothesis
    B. You are certain that the population mean is 30.
    C. You cannot reject the null hypothesis.
    D. The probability of type II error is 0.08
    E. None of the above.
A

C

If P-Value is bigger then you cannot reject null hypothesis.

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12
Q
  1. A researcher has taken a random sample of more than two items. Compared with the population standard deviation, the standard error of the mean is?
    A. Larger than the population standard deviation.
    B. Smaller than the population standard deviation.
    C. The same as the population standard deviation.
    D. Sometimes larger and sometimes smaller than the population standard deviation.
    E. None of the above.
A

D

Slide 98

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13
Q 
13. A manufacturer of children’s toys claims that exactly 5% of all his producing are defective.  When 500 toys from today’s outputs were examined 0.8% were found to be defective.  The 500 toys is?
A. The parameter
B. The statistic
C. The population
D. The sample
E. None of the above.
  1. What is the population of interest?
  2. What is the sample?
  3. What is the parameter?
  4. What is the statistic?
  5. Does the value 5% refer to the parameter or the statistic?
  6. Is the value 8% a parameter or a statistics?
    Statistics
A

D
Might be Sample because, the 500 toys from today’s output were made today. NOT all the toys from the manufacturer

Slide 103

  1. Complete production run
  2. Sample is 500 toys
  3. Proportion of the production run that is defective (5%)
  4. Proportion of the sample toys that are defective (8%)
  5. Parameter
  6. Statistics
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14
Q
  1. A researchers is studying registered voters in Los Angels to see if they favor the city of Los Angels being divided into boroughs (smaller governmental units within the structure of the city). He asks 350 voters to tell him if they would vote for a plan that would implement a borough system in Los Angels. Out of the 350, 235 said they were in favor of the plan. The population is?
    A. The 235 voters in favor of the borough plan.
    B. The 350 voters
    C. All the voters in favor of the borough plan.
    D. All the voters in Los Angeles
    E. None of the above.
  2. The sample is?
A

Population: Collection of all item.
All Voters in Los Angeles.

D.

  1. The sample is the 350 voters
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15
Q 
15. A market researcher has interviewed 80 heads of house holds and recorded whether the person was never married, divorced, windowed, or married.  The data is?
A. Discrete
B. Continuous
C. Qualitative
D. Binomial 
E. None of the above
A

C

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16
Q
  1. A car dealer is studying his customers and the cars they buy. It is appropriate for him to use a mean to describe?
    A. The color of the car bought by a typical customer.
    B. The zip code of a typical customer.
    C. The mileage in miles per gallon of the car bought by a typical customer
    D. The city of residence of the typical residence.
    E. None of the above.
A

C

Slide 4

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17
Q 
17. Given that a sample of 25 had E(x)=75, and E (x-x) squared =48, the mean and standard deviation are?
A. x=3.0 and s=48/25
B. x=3.0 and s=48/24
C. x=3.0 and s=square root of 48/24
D. x=3.0 and s=square root of 48/25
E. None of the above
A 
C
X=E(X) / Sample
X=75/25
S= Squared/ Sample - 1
S= 48/ 25-1
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18
Q 
18. A sample of dental offices found the numbers of cavities filled in the last week to be as follows: 12, 4, 4, 12, 12, 10.  The median number of cavities filled is?
A. 8
B. 9
C. 10 
D. 11
E. 12
A

D

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19
Q
  1. Suppose that, in testing situation with a population that is normally distributed, the null hypothesis is that the population mean is equal to 41. A sample of size 36 had a sample mean of 41 and sample standard deviation of 2. which of the following is correct?
    A. You should reject the null hypothesis
    B. You are certain the population mean is 41
    C. You cannot reject the null hypothesis
    D. You must know the population standard deviation to complete the test
    E. None of the above
A

C

You cannot reject the null hypothesis when not much of a difference in population mean and sample size. (Or maybe sample mean is bigger then sample size?)

Slide 91

Since population standard deviation is unknown, use confidence interval:

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20
Q
  1. Which of the following is ALWAYS true for test of hypothesis?
    A. The null hypothesis contains
A

E

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21
Q
  1. A sample of 100 receipts from a restaurant showed that 12 had errors. What is the 95% confidence interval for the proportion of all receipts that have error? Note that 20.025= 1.96 and t 0.025= 1.984 for 99 degrees of freedom?
    A. 0.12 +- (1.96) square root of (0.12)(0.88)/100
    B. 0.12 +- (1.984) square root of (0.12)(0.88)/100
    C. 0.88 +- (1.96) square root of (0.12)(0.88)/100
    D. 0.12+-(1.96) square root of (0.12)(0.5)/100
    E. None of the above
A

A

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22
Q 
22. If you have data on product output and total cost of production, you can estimate fixed and variable cost by using?
A. Bayes rule
B. A confidence Interval
C. A hypothesis test
D. Linear regression
E. None of the above
A

D

Bayes isn’t even in here

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23
Q 
23. The postal service has recently raised the price of a first class stamp by three cents to 37 cents.  While you were in the post office, you saw 30 three cent stamps sold and 20 of the new 37 cents stamps sold.  What was the average price paid for a stamp while you were in the post office?
A. 8.3 cents
B. 16.6 cents
C. 20 cents
D. 25 cents
E. none of the above
A

B

30 > 3 cents
20 > 37 cents

303=90
3720=740

740+90=830

30+20=50
830/50

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24
Q

An investor has purchased stock in a firm. The investor believes that , at the end of the year, there is
0.10 probability that the stock will show a $6,000 profit,
0.30 probability that the stock will show a $4000 profit and
0.60 probability that the stock will show a $2000 loss.
The expected profit is $600.

If the best profit increases by $1000 from $6000 to $7000, the expected profit?
A. Will remain unchanged
B. Will increase by $10
C. Will increase by $100
D. Will increase by a $1000
E. None of the above
A

C

Because

0.106000=600
0.107000=700
Difference 100$

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25
Q 
25. The number of hours in the life time of a light bulb is a random variable of which type?
A. Binomial
B. Poison
C. Continuos
D. Discrete
E. None of the above
A

C

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26
Q

\Which of the following in NOT an assumption that is required for the use of the binomial formula?
A. The trial are independent
B. The probability of success is the same for every trial
C. Each trial has only two possible outcomes
D. The random variable is the number of success out of N trials
E All of the above assumptions are required

A

E

Slide 83

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27
Q

27.A survey was conducted in July, 2002 of 200 of the 6000 CSUN business students. The survey asked the questions: Are you taking BUS 301 in the fall? Twenty percent of the 200 students said yes. Using this information?
A. The college knew exactly how many sections of BUS 301 to schedule
B. The College knew exactly how many how many sections of bus301 to schedule, but didn’t know how many should be at night
C. The college knew the maximum number of section of bus 301 necessary
D. The college didn’t have enough information to be sure of how many sections to schedule
E. None of the above

A

D

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28
Q
  1. If a television rating service surveyed 800 viewers and 700 watched American Idol, the population is?
    A. The 800 viewers surveyed
    B. The 700 viewers who watched American idol
    C. The 100 viewers who did not watch American idol
    D. All television viewers
    E. None of the above
A

D

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29
Q 
29. You survey your friends and ask them which type of movie (action, comedy, romance, horror) they prefer.  Which of the following graphical displays would be most appropriate to display the data?
A. Scatter diagram
B. A least squares regression line
C. A box plot
D. A bar chart
E. None of the above
A

D

Genre=Qualitative

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30
Q 
A car manufacturer states on the window sticker of its new cars: 38 MPG Highway.  This is an example of?
A. A mean
B. A proportion 
C. A standard deviation
D. A range
E. None of the above
A

A

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31
Q

A study of the number of cars sold looked at the number of cars sold at 500
Dealers The smallest dealer had 11 cars sold and the largest had 154 cars sold. If you were going to create a frequency distribution of the number of cars sold using six classes in your frequency distribution, which of the following might be a
reasonable first class?

a. 0 to 25
b. 0 to 35
c. 5 to 35
d. 10 to 35
e. none of the above

A

(Wrong) Not A

???

Incorrect. Please review Top Ten Concept # 1.

Maybe D

Frequency Distribution: class width =
Max-Min/ (# of classes)

Therefore.
154-11= 143
143/6=22

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32
Q

(3) Which of the following is always true for a test of a hypothesis?
(a) The type ll error is more important than type l error (b)  is larger then 
(c )  is the probability of a type ll error (d) A type l error occurs when you
accept the null hypothesis when it is not true (e) None of the above is true

A

E

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33
Q

(4) Suppose that, in attesting situation with a population that is normally distributed,
The null hypothesis is that the population mean is equal to 41. A sample of size 36 had a sample mean of 41 and sample standard deviation of 2. Which of the
following is correct?

A

(b) You cannot reject the null hypothesis

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34
Q

(5) If you take a sample of size 24 from a normal population for which you do not know the population standard deviation and want to calculate a 95% confidence interval for the mean, which is not need?

A

(c) The value of Z0.025

This is the answer. Therefore you don’t need the Z

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35
Q

(6) The coefficient of determination, R²

A

(b) Tell us how close the Regression line fits the points in a scatter
diagram.

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36
Q

(8) The retail price of a product is $5 per unit & the cost of production is $2 per
unit. If the expected number of unit sold is 4, the expected profit will be

A

(b) 12 ($5 profit per unit - $2 cost per unit = $3 * 4 unit sold = 12)

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37
Q

s not assumption that is required for the use of binomial formula?
(a) The trails are independent
(b) The probability of success is the same for
ever trail.
(c) Each trail has only 2 possible outcomes
d) The random variable
is the number of successes out of a trails
(e) All of the above.

A

E

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38
Q

You are measuring the life time of a light bulb. Which of the following might be
the distribution of this random variable?
(a) Binomial (b) Normal (c) Poisson (d) All three (e) None

A

B

Measurement (dollars, inches, years)
Mean=medium=mode

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39
Q

If the P value is less then Alpha, you

A

(c ) Should reject the null hypothesis.

40
Q

Because of the variation in the measured contents of a can of cola,

A

(b) The average contents of a sample of 10 cans will give us the average contents for the day’s production of 100,000 cans.

41
Q

A manufacturer of children’s toy claims that exactly 5% of all his products are defective. When 500 toys from today’s output were examined, 8% were found to be defective. What is the parameter?

A

(b) The % of all the toys made that are defective.

42
Q

X claims that the average box of X contains 12 ounces. You bought 1 box at each 5 different grocery stores. The weights were 13.1, 11.6, 12.1, 12.3 & 11.9 ounces.
The mean weight of the 5 boxes are?

2.The sample is

A

E None of the above
Mean=12.2

13.1 - 12.2= 0.9…. Squared= 0.81
11.6 - 12.2= -0.6…. Squared= 0.36
12.1 - 12.2= -0.1…. Squared= 0.01
12.3 - 12.2= …. 0.1 Squared= 0.01
11.9 - 12.2= …. -0.3 Squared= 0.09
Add 0.8-0.09 / 5

2.maybe 5?

43
Q

A car manufacturer is studying the relationship between the weight of its vehicles
and the mileage they get in city driving. Which following would an analyst for the company construct to aid in this study?

A

(b) The least squares regression line.

44
Q

Which of the following is NOT quantitative date?

A

(c ) Whether a driver buys premium gasoline or not

45
Q

A basketball player scored 12, 25, 16, & 13 points in her last 4 games. What is the mean number of points per game she scored during this period?

A

(c) 16.5

46
Q

The sample 10, 18, 20 has a standard deviation of

A

(b) 5.29 [(36+4+16) ÷ 2] = 56 ÷ 2 = √28 = 5.29

  1. Add all. 10+18+20=48
  2. There are 3 numbers so… 48/3=16
  3. 10-16=-6… 18-16=2… 20-16=4
  4. 36+4+16=56
  5. 56/ (3-1)= 56/2= 23

51/n-1= 51/3-1= 51/2=25.5
25.5 Sqr Root= 5.04

47
Q

Which of the following is NOT one of the steps in hypothesis testing?

A

Calculate the sample Z-value (test statistic)

-Hypothesis does not require Z-Value testing

48
Q

An urban planner wished to determine whether there is sufficient evidence to conclude that the mean family income in the San Fernando Valley exceeds $38000.
When the urban planner collects data on family incomes, he would –

A

(a) Use a one-tailed test with the alternative to the right (above $38000)

The word Exceed

49
Q

A study was conducted in Malibu on the value of a house (Y, in thousands of dollars) as it relates to the distance the house is from the beach (X, in miles). The result was the regression equation, Y= 800-20X. In the equation, the number 20 represents.

A

(c) For each extra mile a house is from the beach, the price drops by $20,000

(Miles and Dollars are involved)

50
Q

The probability distribution of Z is:
X 1, 2, 3, 4
P(X) .30, .35, .20, .15
What is the expected number of children in a randomly selected Canadian household? Let X represent the number of children in Canadian household.

A

(B) 2.2

Expected Numbers. X and P(X)
1*.30= .30
2*.35=. .70
3*.20= .60
4*.15= .60

.30+.70=1.0
.60+.60=1.2
=2.2

51
Q

A sales representative make 3 in person visits to customers every morning. Out of the 3 visits, she will make either 0, 1.3 or 3 sales. The probabilities are 0.2, 0.4, 0.3, and 0.1, respectively. For each sale, she gets a commission of $100. Her expected commissions for one morning’s visits are…

A

30

14.2
Add
???

52
Q

The binomial distribution is a distribution.

(a) Which is always symmetric
(b) Can always be used when sampling without replacement
(c) Which always takes integer values
(d) Which is always more spread out than the normal distribution
(e) None

A

E
I think it might be C
Is it C? I’m not sure. Never tried it on a test.

???

53
Q

A random variable is found by sampling classes at CSUN and counting the number of those classes with over 200 students enrolled. Which of the following distributions might be the distribution of this random variable.

A

Normal

54
Q

For a given hypothesis test, the null hypothesis can be rejected at the 0.05 level of significance. We can infer that P-value.

A

(a) Is less than 0.05

55
Q

When you increase the size of your sample from a population,

(a) You decrease the population standard deviation
(b) You increase the standard deviation of the sample mean
(c) You decrease the standard deviation of the sample mean
(d) You decrease the sample standard deviation
(e) None

A

C

Increase size of sample of population you decrease the SD

56
Q

A summary measure computed from a&raquo_space;>sample«< is a

A

Statistic

57
Q

A manufacturer of children’s toys claims that exactly 5% of all his products are defective. When 500 toys from today’s output were examined, 8% were found to be defective. What is the sample?

A

500 toys

58
Q

A student took a sample of 25 textbooks from the bookstore and recorded the costs of the books. The student wants to know whether the mean cost of all textbooks is greater than $75. The student should,

A

(e) Test the null hypothesis that the mean cost of all textbooks is equal to $75.

59
Q

Reasons to calculate the mean of a data set

a. find range
b. find smaller number
c. find middle number
d. find measure of location
e. None of the above

A

D

60
Q

. Ho: π= .6 H1: π >.6 sample is 250 p=.63 z=.97 sig.=.05 critic. z=1.64

    a. reserve null hypothesis
    b. reject null
    c. accept alternative 
    d. conclude π> .6
    e. none of above
A

Step One Ho: π = .6
H1: π >.6 (upper tail)

Step Two Test statistic Z
Z = (.63 - .6)/ sq rt[(.6 x .4)/ 250] = .97

Step Three Rejection Region (sig = .05) z = 1.64

Step Four Conclude: since .97

61
Q

There is a .20 probability that stock will profit 3000. There is a 10 probability that stock will profit 6000. There is a .70 probability that stock will lose -2000 losses. What is expected profit?
a. -2000 b. 2333 c. 2600 d. 3667 e. none

A

A

.203000= 6000
.106000= 6000
6000-6000=0

.70*-2000=-2000

=-2000

62
Q

Which is NOT characteristic of normal distribution.

    a. symmetric distribution
    b. mean is 0
    c. mean, median, mode is equal
    d. distribution is bell shaped
    e. all of the above
A

B or E. Maybe B
They are all symmetric
All mean median mode is equal
It is bell shaped

E Is incorrect

63
Q

P value is > α you

A

Accept Null hypothesis

64
Q

Sampled 20 banks and recorded rates for 30 yrs. Data is:

a. discrete property that the number of possible values is either a finite number or a “countable” number, which results in 0 possibilities, or 1 possibility or 2 possibilities and so on.
b. continuous Result from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions or jumps
c. qualitative -data that can be separated into different categories distinguished by some nonnumeric characteristic
d. binomial is an abstraction of the intuitive concept of chance into the theoretical domains of mathematics, forming the foundations of probability theory and mathematical statistics

A

B/E?

Maybe B?

???f

65
Q 
The distribution of home prices is often positively skewed (skewed to the right).  In such a case, it is likely that
Select one:
a. the mean is equal to the median
b. the mean is greater than the median  
c. the median is greater than the mean
d. the distribution will have two modes
e. none of the above
A

B

66
Q

Not a step in hypothesis testing

A

Calculate the sample Z-value (test statistic)

???

67
Q

Which of the following statement is correct?

A

Expected value of a random variable is the long run average assuming
the experiment is repeated many times.

68
Q

The correlation coeffiect “r”

A

Measure the relative relationship between 2 variable

69
Q

Hypothesis test, the null hypothesis can be rejected at the 0.05 level of significance. We can conclude that the p-value

A

is less than 0.05

70
Q

Sample of 20 CSUN students found the age of each student……

A

The highest age is at least twice the average age NOT THIS

71
Q 
115. Which of the following is NOT measure of location or central tendency?
A. Mean
B. Mode
C. Range 
D. Median
E. None
A

C

Is in Central Tendency is Mean, Median, Mode
The 3 M’s=Central Tendency

72
Q 
X      0      1        2
P(x)   0.1    0.6    0.3
    The  expected value of X, E(x) is
A. 1.0
B. 1.2
C. 1.5
D. 0.3
E. None
A

B

Expected Value
1.06= .6
2.03= .6

=1.2

73
Q

The expected value of a random variable is the long run average value assuming the experiment is repeated many times T/F

A

True

74
Q 
A researcher for a major bank has sampled 20 other banks and recorded their current interest rates for a 30 year mortgage.  The data is (On test)
Select one:
a. discrete
b. continuous 
c. qualitative
d. binomial
e. none of the above
A

B
Continuous since the interest rate is a number that has decimals/ and could be fractional.
B.

75
Q
  1. Reason to calculate the mean
    a. Find Range of data
    b. Find smallest number
    c. Find middle number
    d. Measure of the location or central trend of numbers in the data set
    e. None
A

D

76
Q

You are testing the hypothesis.&raquo_space;Smaller

A

B

Smaller p-value indicates support for the alternate.
B.

77
Q

A cable company is attempting to show that the average amount spent on cable television per household in the San Fernando Valley is greater than $60 a month. The most appropriate formulation of the hypotheses is

A

H0=60 : 60>a

78
Q 
In order to determine the average profit per patient, a hospital is planning on taking a random sample of its billing records and computing a confidence interval for the average amount.  Four possible options with different sample size are under consideration.  Which one will produce the narrowest interval?
Select one:
a. n = 100  
b. n = 200
c. n = 300
d. n = 400
e. none of the above
A

The larger your sample size, the more sure you can be that their answers truly reflect the population. This indicates that for a given confidence level, the larger your sample size, the smaller your confidence interval.

D.

NOT
a. n = 100
Incorrect. Please review Top Ten Concept # 3.

79
Q

Simple linear regression involves the use of
Select one:
a. one independent and one dependent variable.
b. only independent variables.
c. several dependent variables and one independent variable.
d. several independent variables and one dependent variable.
e. none of the above

A

Probably A?

yea, probably A.

Y=mx + b.
Y is the dependent, and the x is independent.

Not
d. several independent variables and one dependent variable.
Incorrect. Please review Top Ten Concept # 4.

80
Q 
The number of defective light bulbs in a sample of five is an example of which random variable?
Select one:
a. normal 
b. binomial
c. exponential
d. student t
e. none of the above
A

The key difference is that a binomial distribution is discrete, not continuous. The number of defective bulbs is discrete, and binomial.
(It says sample therefore binomial)

Normal would be continuous, like taking a sample of average women’s heights in the US.

B.

Not
a. normal
Incorrect. Please review Top Ten Concept # 6.

81
Q

You are conducting a one-sided test of the null hypothesis that the population proportion is 0.40 versus the alternative that the population proportion is greater than 0.40. The p-value is 0.67. If the level of significance is 0.05, you should
Select one:
a. reject the null hypothesis because 0.67 is greater than 0.05.
b. reject the null hypothesis because 0.67 is greater than 0.40.
c. not reject the null hypothesis because 0.67 is smaller than 0.05.
d. not reject the null hypothesis because 0.67 is greater than 0.05.
e. none of the above

A

D (Correct)

Ho: pi = .40
Ha: pi > .40 (lower tail)

the probability for the .05 level of significance is .52 on a z table.

.67>.52 so it is outside of the rejection zone: dont reject the null.

D.

82
Q

Males and females have automobile accidents with the same average cost of repair, but the variation in the cost of repair is greater for the accidents of men. Assuming costs of repair are normally distributed, (
Select one:
a. men have a greater chance of having a very costly accident.
b. men have a smaller chance of having a very costly accident.
c. men have a greater chance of having an accident close the average cost.
d. there is no difference between men and women with respect to the cost of automobile accidents.
e. none of the above

A

Maybe A

High Variation = uncertainty, high standard deviation.
Since variation is high in cost of repair for men, they have a great a greater chance of a costly accident?

A. maybe

Not
c. men have a greater chance of having an accident close the average cost.
Incorrect. Please review Top Ten Concept # 8.

83
Q

A manufacturer of children’s toys claims that exactly 5% of all his products are defective. When 500 toys from today’s output were examined, 8% were found to be defective. What is the population of interest?
Select one:
a. The 500 toys.
b. All the toys made today.
c. All the toys made by this manufacturer.
d. The 40 defective toys.
e. none of the above

A

C

84
Q

A researcher is studying registered voters in Los Angeles to see if they favor the City of Los Angeles being divided into boroughs (smaller governmental units within the structure of the city). He asks 350 voters to tell him if they would vote for a plan that would implement a borough system in Los Angeles. Out of the 350, 235 said they were in favor of the plan. The sample is
Select one:
a. the 235 voters in favor of the borough plan.
b. the 350 voters.
c. all the voters in favor of the borough plan.
d. all the voters in Los Angeles.
e. none of the above

A

B

B. you are correct.

Not
d. all the voters in Los Angeles.
Incorrect. Please review Top Ten Concept # 9.

85
Q 
A market researcher has interviewed 80 heads of household and recorded whether there was a DVD player in the household.  The data is (Because your not determining the number or not)
Select one:
a. discrete
b. continuous
c. qualitative 
d. normal 
e. none of the above
A

qualitative: yes or no answer (something non numeric).
discrete: solid integer
continuous: numbers between a range (like between 1 and 2; 1.5, 1.65, 1.412412452151, etc).

Normal is continuous o:

C.

Not
d. normal
Incorrect. Please review Top Ten Concept # 10.

86
Q

A study of the number of cars sold looked at the number of cars sold at 500
Dealers The smallest dealer had 11 cars sold and the largest had 154 cars sold. If you were going to create a frequency distribution of the number of cars sold using six classes in your frequency distribution, which of the following might be a
reasonable first class?

a. 0 to 25
b. 0 to 35
c. 5 to 35
d. 10 to 35
e. none of the above

A

Range:
154 -11: 143

143/ 6 = 23.833… ~ 24 (approximately 24 or 25 per class width).

Lowest value: 11 (10 is lower than 11 so it’s a reasonable start)
Highest value: 154

Might be D.

Not
a. 0 to 25
Incorrect. Please review Top Ten Concept # 1.

87
Q

A homeowner is interested in whether the thermostat on her heating system is working correctly (i.e., the temperature in the house will be what is set on the thermostat). She set the thermostat at 72 degrees and took 24 random temperature measurements in her house over a three day period. The alternative hypothesis about the temperature in the house should be
Select one:
a. the mean temperature is greater than 72
b. the mean temperature is equal to 72
c. the mean temperature is not equal to 72
d. the mean temperature is less than 72
e. none of the above

A

C

88
Q

You are testing the hypothesis . The standard deviation is known to be 5. A sample of 100 had a mean of 78. Using a significance level of a = 0.05, which of the following is correct:
Select one:
a. Since the sample mean is four standard deviations below 80, we conclude that μ = 80
b. Since the sample mean is less than the critical value of 79.18, we conclude that μ > 80
c. Since the z-value is less than the critical z-value of -1.645, we conclude that μ = 80
d. Since the sample mean is four standard deviations below 80, we conclude that μ

A

D

89
Q

After constructing a 90% confidence interval, you decide you cannot show your interval to your supervisor because the interval is too wide. In order to correct the problem and give a meaningful confidence interval to your supervisor, your best course of action is to
Select one:
a. decrease the population standard deviation.
b. collect more data (increase the sample size).
c. lower the confidence level to 75%.
d. fudge the data.
e. none of the above is a very good choice

A

B

90
Q

Which of the following statements is correct?
Select one:
a. The expected value is the square root of the mean.
b. In a distribution that is skewed to the left (negatively skewed), the mean is less than the expected value.
c. The expected value of a random variable is the long run average value assuming the experiment is repeated many times.
d. The expected value is the square of the mean.
e. none of the above

A

C

91
Q

The expected return from a bet of $1.00 in a casino is $0.94. This means that
Select one:
a. if you bet $1000 in next visit to the casino, you will return home with $940.
b. if you visit the casino repeatedly, your chances of winning increase.
c. in the long run, you will lose 6 cents of every dollar you bet.
d. if you bet $106, you will expect to break even.
e. none of the above

A

C

92
Q

The&raquo_space;>higher

A

There’s a low and high (Trick question)
I think it’s A?
???

NOT B

I think it’s A?

93
Q 
A summary measure computed from a population is a
Select one:
a. parameter.
b. statistic.  
Incorrect. Please review Top Ten Concept # 9.
c. population.
d. sample.
e. none of the above
A

A

NOT B

94
Q 
A market researcher has interviewed 80 households and recorded the number of TV sets in each household.  The data is
Select one:
a. discrete
b. continuous
c. qualitative  
Incorrect. Please review Top Ten Concept # 10.
d. binomial
e. none of the above
A

NOT C OR D

95
Q

Which of the following is NOT a characteristic of a normal distribution?
Select one:
a. It is a symmetric distribution.
b. The mean is always zero.
c. The mean, median, and mode are all equal.
d. The distribution is bell or mound shaped.
e. all of the above are characteristics of a normal distribution
Incorrect. Please review Top Ten Concept # 6.

A

?? Maybe B?

NOT E

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