K579 SPRING 2017

EXERCISES ON DESCRIPTIVE STATISTICS

Exercise #1

1. Summarize the salary data using summary(). Then use describe from the psych

package. Compare the two methods.

2. What are the counts of men and women by rank? Also, compute the proportions of the

total number; column proportions; row proportions.

3. Draw a histogram for years of service. Add a density line in red.

4. Draw a box plot for salary.

5. Draw a box plot for salary by rank. Make it horizontal.

6. Create a QQ plot of salary. What does the QQ plot tell you?

Exercise #2

1. Read the data set retaildata.csv into an object retail.

2. List the first few rows and last few rows of retail.

3. Plot age (x-axis) vs. credit score (y-axis).

a. Add title, "Customer Credit Score vs. Age".

b. Set the plot characters to filled circles; make the color red.

c. Label the x and y axes.

d. Set the limits of the x and y axes appropriately.

e. Draw lines on the graph at the mean age and the mean credit score. The lines

should be dark blue and dotted and of weight 1.25.

4. Count how many customers are under the average age and have lower than average

credit scores.

Exercises On Descriptive Statistics

Experimental Course In Decision Support Modeling (BUS K579)