MBAD 503

Question 1

Best illustrates the distinction between statistical significance and practical importance

Answer 1

Increased life of hard drive from 240,000 to 250,000 hours

Question 2

25% Students in stats class watch 8+ hours of TV a week so I conclude 25% of university students do the same. Which fallacy is this?

Answer 2

Uses a sample not representative of all the students

Question 3

NASA Challenger and Columbia disasters suggest that

Answer 3

Limited data may still contain important clues

Question 4

Smoking isn’t harmful, my aunt lived to 90, illustrates which fallacy

Answer 4

Small sample generalization

Question 5

Bob didn’t wear lucky T shirt to class so he failed his test, illustrates which fallacy

Answer 5

Post hoc reasoning

Question 6

T/F. Statistics is the science of believability

Answer 6

True

Question 7

Characteristics of the statistically - savvy

Answer 7

Technically current
Communicates well
Can deal with imperfect information

Question 8

Which are practical constraints facing a business researcher

Answer 8

Time and money are limited
Research on humans is fraught with danger and ethics
The world is no laboratory so some things are impratical

Question 9

Which is not true?

Inconsistent treatment of data by researcher is a symptom of poor survey or research design
Science of stats tells us whether the sample evidence is convincing
The post hoc fallacy says that when B follows A then B is caused by A
Valid statistical inferences may be made when sample sizes are small the the rules are followed for handling them.

Answer 9

Inconsistent treatment of data by researcher is a symptom of poor survey or research design

Question 10

Bond rating from firms like B+, AA, etc are examples of which measurement of data?

Answer 10

Ordinal

Question 11

Type of charge card is an example of which kind of variable?

Answer 11

Nominal

Question 12

Duration of a flight is an example of which kind of variable?

Answer 12

Continuous Ratio

Question 13

Number of Nobel prize winning faculty at Oxnard U is an example of which kind of data measurement?

Answer 13

Discrete Ratio (involves zero)

Question 14

Temp in degrees Celsius at 7:00am today is an example of which measurement of data?

Answer 14

Continuous Interval

Question 15

T/F. Cluster Sampling is useful when strata characteristics are unknown?

Answer 15

True

Question 16

Before deciding to asses heavy fines on noisy airlines, which sampling method would the FAA probably use to measure peak noise of jets departing?

Answer 16

Stratified Sample

To record aircraft size, type, carrier for a week and use this to construct a stratified sample

Question 17

Sampling Bias can best be reduced by?

Answer 17

Random Sampling

Question 18

If we use a random number generator between 0-99, we would most likely find that

Answer 18

Some numbers would occur more than once

Question 19

Which describes the observations in a dataset consisting of the GPAs and credits taken in the current quarter for randomly selected EWU students?

Answer 19

The EWU students

Question 20

What is a time series variable

Answer 20

Net earnings reported by Xenia Corp. for the last 10 quarters

Question 21

CDC wants to estimate extra hospital stay that occurs when pts experience post op a-fib. They divide the USA into 9 regions. In each region, hospitals are selected at random which each hospital size group. In each hospital, surgery pts are sampled according to known percentages by age, gender, etc.
Which sampling methods are used?

Answer 21

Cluster
Stratified
Simple Random

Question 22

T/F. Running times for 500 runners in a race would be a univariate data set.

Answer 22

True

Question 23

T/F. List of the ages, genders, salaries, years of experience for 50 CEOs is a multivariate data set.

Answer 23

True

Question 24

Bond ratings for Aardco INC are B+ while bonds of Deva Corp are AA. Which level of measurement would be appropriate for this data?

Answer 24

Ordinal

Question 25

Auto exhaust emission of CO2 is what kind of data measurement?

Answer 25

Ratio

Question 26

Number of passengers bumped on a particular flight is what data measurement?

Answer 26

Ratio

Question 27

What sampling method is quicker and easier?

Answer 27

Convenience

Question 28

Professor chose 7 students from his stats class of 35 students by picking those with red shirts that day. Which kind of sample is this?

Answer 28

Convenience

Question 29

30 work orders are selected from a filing cabinet of 500 by choosing every 15th folder. Which sampling method is this?

Answer 29

Systematic

Question 30

A population has groups with a small amt of variation within them but large variation among or between the groups themselves. The proper sampling technique is?

Answer 30

Stratified

Question 31

A manager chose 2 people from his team of 8 to give an oral presentation because he thought they were representative of the whole teams views. What sampling technique did he use in choosing these 2 people?

Answer 31

Judgement

Question 32

A professor wants to know how many MBA students would take a summer elective and took a survey of the class she was teaching. What kind of sample is this?

Answer 32

Convenience

Question 33

A sampling technique used when groups are defined by their geographical significance is?

Answer 33

Cluster

Question 34

Which is not an area of application of statistics in business?

Answer 34

Questioning executives strategic decisions

Question 35

Students evaluation of a professors teaching is an example of which measurement type?

Answer 35

Interval

Question 36

Tom’s SUV rolled over. SUVs are dangerous. This best illustrates which fallacy type?

Answer 36

Small sample generalization

Question 37

Your rating of the food served at a restaurant using a three point scale of 0=gross, 1=decent, 2=yummy is what kind of data measurement?

Answer 37

Ordinal (ranking)

Question 38

Frequency Polygon

Answer 38

Line graph connecting the midpoints of the histogram bin intervals plus extra at the beginning and end.

Question 39

Ogive is? | Useful for?

Answer 39

Line graph of the cumulative frequencies. Useful for finding percentiles or for comparing shape with a benchmark.

Question 40

Stem and Leaf plot

Answer 40

Exploratory data analysis tool | Frequency tally

Question 41

Stacked Dot Plot

Answer 41

Compares two or more groups, like home prices in 4 different regions

Question 42

Sturges’ Rule

Answer 42

Bin Width = (Xmax- Xmin)/k

Question 43

Relative frequencies calculation of data in a table

Answer 43

Absolute frequency per bin / total number of data values

Question 44

Cumulative Relative Frequencies

Answer 44

Accumulate relative frequency values as bin limits increase.

Question 45

Histogram

Answer 45

Graphical representation of a frequency distribution Appearance is identical if vertical axis shows frequency, relative frequency, or percent Shows SHAPE of a population.

Question 46

Frequency Polygon

Answer 46

Line graph connecting midpoints of histogram bin intervals at the beginning and end

Question 47

Log Scale is used for

Answer 47

Time series data that could grow at a compound rate, common when period of time is long or for data that grows rapidly.

Question 48

Which is vertical and which is horizontal, bar and column?

Answer 48

Bar is horizontal, column is vertical

Question 49

Pareto chart

Answer 49

Column chart of categorical data in descending order of frequency

Question 50

Stacked column chart

Answer 50

Bar height is sum of several subtotals

Question 51

Scatter Plot

Answer 51

Pairs of observations, starting point for bivariate analysis. Investigate the relationship between 2 variables.

Question 52

Pivot Table

Answer 52

Interactive analysis of a data matrix

Question 53

Row and column data types of a pivot table | Variables must be what kind?

Answer 53

Categorical or discrete numerical | Numerical

Question 54

Nonzero Origin

Answer 54

Exaggerates the trend

Question 55

Elastic graph proportions

Answer 55

Exaggerates trend, to avoid, keep aspect ratio below 2.0

Question 56

Difference between bar and column charts

Answer 56

Bar is qualitative data and column is numerical

Question 57

Which is least likely to be used in choosing bin frequency? Sturges’ Rule Aesthetic Judgement Nice limits Always starting at zero

Answer 57

Always starting at zero

Question 58

Are line charts used for cross sectional data?

Answer 58

No

Question 59

A column chart would not be suitable to display which data?

Answer 59

500 company CEO salaries (too many numbers) | Better would be a histogram

Question 60

What kind of data is allowable for a pie chart?

Answer 60

Categorical / nominal

Question 61

Sturges’ rule

Answer 61

1+3.322 log (number of entries)

Question 62

Attributes of Sturges’ Rule

Answer 62

Just a guideline Purpose is to determine bins to use Double sample size, then add one bin class

Question 63

Pie Charts are popular in business because (3 reasons)

Answer 63

Convey a false sense of science Can be labeled with data to facilitate interpretation Can display major changes in parts of a whole

Question 64

Empirical Rule

Answer 64

Gaussian distribution (bell shaped)

Question 65

How to estimate sigma (range)?

Answer 65

(Xmax-Xmin)/6

Question 66

How to find quartiles?

Answer 66

Find the median then the median of the bottom half and the top half.

Question 67

Box Plot

Answer 67

Exploratory data analysis based on the 5 data summary, Xmax, Xmin, Q1, Q2, Q3

Question 68

Midhinge

Answer 68

Average of first and third quartiles

Question 69

Covariance

Answer 69

Measures the degree which values of x and y change together. If they’re unrelated the covariance is zero.

Question 70

Coefficient of Variation

Answer 70

Standard deviation / mean

Question 71

Which way skewed if mean > median?

Answer 71

Skewed Right

Question 72

Correlation coefficient

Answer 72

The standardized value of the covariance

Question 73

T/F The skewness coefficient is zero in a sample from any normal distribution

Answer 73

False

Question 74

T/F Coefficient of variation cannot be used when the mean is zero

Answer 74

True, because CV = SD/mean

Question 75

T/F Standard Deviation is in same units as the mean?

Answer 75

True

Question 76

Geometric mean is?

Answer 76

Nth root of data points multiplied together where N is the number of data points

Question 77

Disadvantage of the Range is?

Answer 77

Only extreme values are used in its calculation

Question 78

Mode is least appropriate for?

Answer 78

Continuous data

Question 79

Which types of statistics offer robust (resistant to outliers) measures of center?

Answer 79

Median, Midhinge, Trimmed mean

Question 80

Empirical rule says that….

Answer 80

about 32% of the data are beyond one SD from the mean

Question 81

What percentages will lie within the first 3 standard deviations?

Answer 81

68%, 95%, 99%

Question 82

Quick formula for estimating the SD?

Answer 82

Range / 6 OR (Xmax-Xmin)/6

Question 83

Inner fence calculation

Answer 83

``` Q1-1.5(Q3-Q1) = lower inner fence Q3+1.5(Q3-Q1) = upper inner fence ```

Question 84

Outer fence calculation

Answer 84

``` Q1-3.0(Q3-Q1) = lower outer fence Q3+3.0(Q3-Q1) = upper outer fence ```

Question 85

Geometric Distribution

Answer 85

How many Bernoulli trials would it take to get a the first positive result

Question 86

Hypergeometric Distribution

Answer 86

Like Bernoulli but WITHOUT replacement

Question 87

Poisson Distribution

Answer 87

Number of occurrences within a specific unit of measure (like time)

Question 88

Bernoulli Experiment

Answer 88

Random experiment with only 2 outcomes

Question 89

Uniform Distribution

Answer 89

Every outcome has the same change, like rolling a dice

Question 90

Expected Value

Answer 90

Each result multiplied by it’s probability and then all added together, does not have to be an actual option or possible result

Question 91

Binomial Distribution SD equation

Answer 91

Sq.root(nπ(1-π))