Review Exercises 141 4. In general, a histogram is skewed to the left if the is noticeably less than the . 5. A sample of 100 students was asked how many hours per week they spent studying. The following frequency table shows the results: Number of Hours Frequency 1.0–4.9 14 5.0–8.9 34 9.0–12.9 29 13.0–16.9 15 17.0–20.9 8 a. Approximate the mean time this sample of students spent studying. b. Approximate the standard deviation of the time this sample of students spent studying. 6. A sample has a variance of 16. What is the standard deviation? 7. Each of the following histograms represents a data set with mean 20. One has a standard deviation of 3.96 and the other has a standard deviation of 2.28. Which is which? Fill in the blanks: Histogram I has a standard deviation of and histogram II has a standard deviation of . 12 14 16 18 20 22 24 26 28 I 12 10 8 6 4 2 0 Frequency 12 14 16 18 20 22 24 26 28 20 15 10 5 0 II Frequency In Exercises 8–11, suppose that the mean starting salary of social workers in a specific region is $37,480 with a standard deviation of $1,400. 8. Assume that the histogram of starting salaries is approximately bell-shaped. Approximately what percentage of the salaries will be between $34,680 and $40,280? 9. Assume it is not known whether the histogram of starting salaries is bell-shaped. Fill in the blank: At least percent of the salaries will be between $34,680 and $40,280. 10. John’s starting salary is $38,180. What is the z-score of his salary? 11. Find the coefficient of variation of the salaries. 12. True or false: If a student’s exam grade is on the 55th percentile, then approximately 45% of the scores are below his or her grade. 13. The five-number summary for a sample is 7, 18, 35, 62, 85. What is the IQR? 14. The prices (in dollars) for a sample of coffee makers are: 19 22 29 68 35 37 28 22 41 39 28 a. Find the first and third quartiles. b. Find the upper and lower outlier boundaries. c. Are there any outliers? Of so, list them. 15. Construct a boxplot for the data in Exercise 14. Review Exercises 1. Support your local artist: Following are the annual amounts of federal support (in millions of dollars) for National Endowment for the Arts programs for the years 2000 to 2006. Year Amount 2000 85.2 2001 94.0 2002 98.6 2003 101.0 2004 105.5 2005 108.8 2006 112.8 Source: National Endowment for the Arts
navidi_monk_essential_statistics_1e_ch1_3
To see the actual publication please follow the link above