**Practice Problems: Measures of Variability**

A high school teacher at a small private school assigns trigonometry practice problems to be worked via the net. Students must use a password to access the problems and the time of log-in and log-off are automatically recorded for the teacher. At the end of the week, the teacher examines the amount of time each student spent working the assigned problems. The data is provided below in minutes.

15

28

25

48

22

43

49

34

22

33

27

25

22

20

39

- Find the Range, Standard Deviation, and Variance for the above data.

- What does this information tell you about the variability of student's length of time on the computer solving trigonometry problems? Is it homogeneous or heterogeneous?

Answer

Bailey has been playing golf on the weekends for the past three years. Recently, she started keeping track of her recorded scores. Her scores for June and July at her favorite 9-hole (par 36) golf course are provided below.

45

49

42

56

41

36

34

38

41

40

42

41

39

38

40

39

36

41

- Find the Range, Standard Deviation, and Variance for the above data.

- What does this information tell you about the variability of Bailey's golf game?

Answer

Midterm exam scores for a small advanced neuroanatomy class are provided below. Scores represent percent of items marked correct on the exam.

87

99

75

87

94

75

35

88

87

93

- Find the Range, Standard Deviation, and Variance for the above data.

- What does this information tell you about the variability of students' performance on the midterm?

Answer

A group committed to quality television has been concerned about a new talk show. For two weeks, they decide to count the number of words that must be "bleeped" as too obscene for television and the number of physical altercations. They hope that after recording this data that they will be able to argue that the show is inappropriate for television particularly during the day. The data for number of words censored is provided below.

342

267

321

157

33

349

254

166

132

289

- Find the Range, Standard Deviation, and Variance for the above data.

- What does this information tell you about variability of number of words censored per show?

Answer

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