AP Stats Unit 4 Flashcards

Question 1

Q

A poll of 120 Ithacans found that 30 had visited the Museum of the Earth, and that 80 had been to Home Depot. If it appeared that going to Home Depot and going to the Museum of the Earth were independent
events, how many of those polled had been to both ?
A) 10 B) 15 C) 20 D) 24
E) It cannot be determined.

Question 2

Q

Six Republicans and four Democrats have applied for two open positions on a planning committee. Since all the applicants are qualified to serve, the City Council decides to pick the two new members randomly. What is the probability that both come from the same party?
A) 66/90 B) 52/90 C) 52/100 D) 42/90 E) 42/100

Question 3

Q

A national study found that the average family spent $422 a month on groceries, with a standard deviation of $84. The average amount spent on housing (rent or mortgage) was $1120 a month, with standard deviation $212. The expected total a family spends on food and housing is 422+1120 = $1542. What is the standard deviation of the total?
A) $128 B) $148 C) $228 D) $295 E) It cannot be determined

Question 4

Q

Pepsi is running a sales promotion in which 12% of all bottles have a “FREE” logo under the cap. What is the probability that you find two free ones in a 6-pack?
A) 1% B) 11% C) 13% D) 23% E) 97%

Question 5

Q

A supermarket claims that their checkout scanners correctly price 99.8% of the items sold. How many items would you expect to buy, on average, to find one that scans incorrectly?
A) 2 B) 99.8 C) 200 D) 500 E) 998

Question 6

Q

Which of these has a geometric model?
A) The number of black cards in a 10-card hand.
B) The colors of the cars in Wegman’s parking lot.
C) The number of hits a baseball player gets in 6 times at bat.
D) The number of cards drawn from a deck until we find all four aces.
E) The number of people we survey until we find someone who owns an iPod.

Question 7

Q

Which of these is most likely to have a binomial model?
A) The number of black cards in a 10-card hand.
B) The colors of the cars in Wegman’s parking lot.
C) The number of hits a baseball player gets in 6 times at bat.
D) The number of cards drawn from a deck until we find all four aces.
E) The number of people we survey until we find someone who owns an iPod.

Question 8

Q

A friend of yours plans to roll a die 600 times. You watch the first 60 rolls, noticing
that she got only 2 sixes. But then you get bored and leave. If the die is fair, how many sixes do you expect her to have when she has finished the 600 tosses?
A) 80 B) 90 C) 96 D) 100 E) 116

Question 9

Q

The probability that Mary studies for her math test is 0.6. If she studies, the probability she will pass the test is 0.8. If she doesn’t study, the probability she will past the test is 0.4. What is the probability she will pass the test?
A) 0.48 B) 0.64 C) 0.8 D) 0.6 E) 0.4

Question 10

Q

The probability that Mary studies for her math test is 0.6. If she studies, the probability she will pass the test is 0.8. If she doesn’t study, the probability she will past the test is 0.4. If Mary passes the test, what is the probability she studied?
A) 0.25 B) 0.50 C) 0.75 D) 0.48 E) .64

Question 11

Q

If two events (both with probability greater than 0) are mutually exclusive, then:
A. They also must be independent.
B. They also could be independent.
C. They cannot be independent.

Question 12

Q

The payoff (X) for a lottery game has the following probability distribution.
X = payoff      $0      $5
probability     0.8      0.2
A. What is the expected value of X?
B. $0
C. $0.50
D. $1.00
E. $2.50

Question 13

Q

The probability is p = 0.80 that a patient with a certain disease will be successfully treated with a new medical treatment. Suppose that the treatment is used on 40 patients. What is the "expected value" of the number of patients who are successfully treated?
A. 40
B. 20
C. 8
D. 32

Question 14

Q

A medical treatment has a success rate of .8. Two patients will be treated with this treatment.
Assuming the results are independent for the two patients, what is the probability that neither one of
them will be successfully cured?
A. .5
B. .36
C. .2
D. .04

Question 15

Q

The Safe Drinking Water Hotline routinely tracks requests for information about water quality. The table below shows the sources of some of its calls.
Source Telephone Email
Laboratories 44 3
Citizens 1875 118
Consultants 234 19
Environmental 62 1
Governmental 83 7
Schools 64 2
Other 369 14
What is the probability that a request comes from a school given it is an email request?
A) 1/62 B) 1/63 C) 1/82 D) 1/117 E)64/90123

Question 16

Q

At KHS, 5% of athletes play football and some other contact sport, 30% play football, and 40% play other contact sports. If there are 200 athletes, how many play neither football nor any other contact sport?
A) 20 B) 70 C) 80 D) 100 E) 130

Question 17

Q

The Correcto Publishing Company claims that its publications will have errors only twice in 100 pages. What is the approximate probability that Anne will read 235 pages of a 790-page book published by Correcto before finding an error?
A) 0.02% B) 2% C) 5% D) 16% E) 30%

Question 18

Q

The theoretical probability of rolling a 2 or a 6 on one roll of a die is 1/3.  A student who tries to produce the probability by counting successes in repeated trials is most likely to come closest to 1/3 with
A) one roll of the die
B) two rolls of the die
C) three rolls of the die
D) ten rolls of the die
E) one hundred rolls of the die

Question 19

Q

For the sake of efficiency, a shoe company decides to prooduce the left shoe of each pair at one site and the right shoe at a different site.  If the two sites produce shoes with a number of defects reflected by mu(1) = 0.002, sigma(1) = 0.15, mu(2) = 0.005, sigma(2) = 0.18, what is the mean and standard deviation for the number of defects for pairs of shoes produced by this company?
A) mu = 0.00035, sigma = 0.165
B) mu = 0.00035, sigma = 0.0549
C) mu = 0.007, sigma = 0.0549
D) mu = 0.007, sigma = 0.2343
E) mu = 0.007, sigma = 0.33

Question 20

Q

The probability of a certain genetic trait in the general population is 27%.  What is the expected number of people you would need to observe before finding one person with this trait?
A) About 4
B) About 10
C) About 27
D) About 73
E) Not enough information

Question 21

Q

A recent survey of students at John Tukey High School revealed that 18% of the students are in favor of changing the dress code. If you randomly select 15 students from this school, what is the probability that at least three of these students are in favor of the proposal to change the dress code?
A) 0.18^3
B) (0.18^3) * (0.82^12)
C) 15C3 * (0.18^3) * (0.82^12)
D) 1 - [15C0 * (0.82^15) + 15C1 * (0.18) * (0.82^14) +15C2 * (0.18^2) * (0.82^13) ]
E) 1 - [15C0 * (0.82^15) + 15C1 * (0.18) * (0.82^14) +15C2 * (0.18^2) * (0.82^13) + 15C3 * (0.18^3) * (0.82^12) ]

Question 22

Q

On a recent test in an introductory economics course, the meangrade was 42 with a variance of 9.  Suppose that the distribution of students' scores on this test is given by the random variable X.  The professor decides to curve the test by multiplying the scores by 1.5 and then adding 7 more points to the result.  The new mean and standard deviation are
A) 63, 4.5
B) 63, 7.5
C) 70, 4.5
D) 70, 7.5
E) 70, 20.25

Question 23

Q

Given two events A and B, if the probability that A occurs is 0.3, the probability that event B occurs is 0.4, and the probability that A or B occurs is 0.55, then the p(A|B) is
A) 0.120 B) 0.220 C) 0.375 D) 0.500 E) 0.700

Question 24

Q

A game of chance involves rolling a fair die.  If the die shows a 1, you win $4; if it shows a 2, you win $.0.50; and if it shows any other number you win nothing.  If the cost to play the game is $1, what are a player's expected winnings?
A) Lose $0.08
B) Lose $0.25
C) Win $0.08
D) Win $0.25
E) Win $0.75

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AP Stats Unit 4 Flashcards

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