Descriptive Statistics

1. Describe the measures of central tendency. Under what condition(s) should each one be used?

2. Last year, 12 employees from a computer company retired. Their ages at retirement are listed below. First, create a stem plot for the data. Next, find the mean retirement age. Round to the nearest year.
55 77 64 77 69 63 62 64 85 64 56 59

3 A retail store manager kept track of the number of car magazines sold each week over a 10-week period. The results are shown below.
27 30 21 62 28 18 23 22 26 28
a Find the mean, median, and mode of newspapers sold over the 10-week period.
b Which measure(s) of central tendency best represent the data?
c Name any outliers.
d
4 Joe wants to pass his statistics class with at least a 75%. His prior four test scores are 74%, 68%, 84% and 79%. What is the minimum score he needs on the final exam to pass the class with a 75% average?

5 Nancy participated in a summer reading program. The number of books read by the 23 participants are as follows:
10 9 6 2 5 3 9 1 6 3 10 4 7 6 3 5 6 2 6 5 3 7 2
Number of books read Frequency
1-2
3-4
5-6
7-8
9-10
a Complete the frequency table.
b Find the mean of the raw data.
c Find the median of the raw data.

6 The chart below represents the number of inches of snow for a seven-day period.
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
2 5 3 10 0 4 2
a Find the mean, median, and mode.
b Which is the best measure of central tendency?
c Remove Wednesday from the calculations. How does that impact the three measures of central tendency?
d Describe the effect outliers have on the measures of central tendency.

7 A dealership sold 15 cars last month. The purchase price of the cars, rounded to the nearest thousand, is represented in the table.
Purchase price Number of cars sold
$15,000 3
$20,000 4
$23,000 5
$25,000 2
$45,000 1
a Find the mean and median of the data.
b Which measure best represents the data? Use the results to support your answer.
c What is the outlier and how does it affect the data?

8. What do the letters represent on the box plot?

9. The test scores from a math final exam are as follows:
64 85 93 55 87 90 73 81 86 79
a Create a box plot using the data.
b Label the five points on the box plot and include numerical answers from part "a."

10. Using the data and results from Question 9, answer the following questions.
a What is the median?
b What is the range?
c What is the interquartile range?
In a short paragraph, describe the data in the box plot.