Practice Exam 1

1.

Classify the answers to the following questions: (1/2 point each cell)

 

 

Scale

(Nominal, Ordinal, Interval or Ratio)

Quantitative

or Qualitative

Continuous or Discrete

(if applicable)

 

Number of people in your household

 

 

 

 

Arrange the following car features (antilock brakes, power steering, etc.) from worst to best

 

 

 

 

Which age category do you belong:

Under 25

25-40

40-65

Over 65

 

 

 

 

Rate store service:

Poor Excellent

1 2 3 4 5 6 7 8 9 10

 

 

 

 

What brand of beer do you drink the most?

 

 

 

 

How many shares of stock do you own?

 

 

 

 

How much do you weigh?

 

 

 


2.


The following is a sample of times (in minutes) customers have to wait in line before being served at a bank:

 

5.5

14.5

6.0

5.5

5.3

5.8

11.0

6.1

7.0

14.5

10.4

 

4.6

4.3

7.2

10.5

6.5

3.3

7.0

4.1

6.2

10.4

4.9

 

Tabulate the data using reasonable intervals (3 points):


  1. Create and plot a relative frequency distribution (4 points) - remember to label all axis clearly:

 
  1. Customers have been complaining about the wait and the bank wants to offer $5 for any customers who waits past a given amount of time. Create and plot a cumulative histogram. What should be the cut-off time if 80% of the customers will NOT be asking for payment? Show this cut-off time on the histogram. (5 points)






















The bank calculates that covering 80% of their customers will cost them too much. They want to cut the cost in half. What cut-off time should they set? (3 points)


 




e) Create a stem-leaf of the same data, labeling leaf units. (4 points)
Leaf units are .1 minutes























f) What is the mean? (3 points)

 






g) What is the median? (3 points)


 

  1. What is the mode? (3 points)

3.

The following are sample wind speeds from two samples:

 

North Carolina

Florida

 

102

95

 

109

110

 

93

90

 

105

100

 

97

98

 

101

97

 

99

92

 

111

93

 

Find the mean of the North Carolina sample. (3 points)

Find the mean of the Florida sample (3 points)

Calculate the standard deviation of the North Carolina sample. You must show all calculations for full points.

 

Assume the standard deviation of the Florida sample is 6.24 miles/hour. Compare the two distributions, what can you say in comparing the distribution of wind speeds of hurricanes of Florida versus North Carolina? (5 points)

 

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