1. The number of sick days due to colds and flu last year was recorded by a sample of 15 adults. The data are:
5 7 0 3 15 6 5 9 3 8 10 5 2 0 12
Compute the mean, median, and mode.
2. Suppose that you bought a stock 6 years ago at $12. The stock's price at the end of each year is shown here
Year 1 2 3 4 5 6
Price 10 14 15 22 30 25
a. Compute the rate of return for each year.
b. Compute the mean and median of the rates of return.
c. Compute the geometric mean of the rates of return.
d. Explain why the best statistic to use to describe what happened to the price of the stock over the 6-year period is the geometric mean.
3. Examine the three samples listed here. Without performing any calculations, indicate which sample has the largest amount of variation and which sample has the smallest amount of variation.
Explain how you produced your answer.
a. 17 29 12 16 11
b. 22 18 23 20 17
c. 24 37 6 39 29
4. A set of data whose histogram is bell shaped yields a mean and standard deviation of 50 and 4, respectively. Approximately what
proportion of observations
a. are between 46 and 54?
b. are between 42 and 58?
c. are between 38 and 62?
5. Compute the interquartile range from the following data.
5 8 14 6 21 11 9 10 18 2
6. Draw the box plot of the following set of data.
9 28 15 21 12 22 29 20 23 31 11 19 24 16 13
7. The covariance of two variables has been calculated to be -150. What does the statistic tell you about the relationship between the two variables?
8. A retailer wanted to estimate the monthly fixed and variable selling expenses. As a first step she collected data from the past 8 months. The total selling expenses (in $thousands) and the total sales (in $thousands) were recorded and listed below.
Total Sales Selling Expenses
20 14
40 16
60 18
50 17
50 18
55 18
60 18
70 20
a. Compute the covariance and the coefficient of determination and describe what these statistics tell you.
b. Determine the least squares line and use it to produce the estimates the retailer wants.
9. Describe the concept that you had the most difficulty understanding. How does it apply to being a manager in your chosen field?