Dr. Felicity Bark carried out a research study to see if female and male dog owners differed with respect to the time that they spent talking to their dogs. She randomly selected 15 female dog owners and 10 male dog owners from a pool of volunteers. Each owner-dog pair was placed, one at a time, in the same room for 4 minutes. The owner-dog dyads were videotaped and the total time that each owner spent talking to his/her dog was recorded. Those data are shown below.

Female Owner Time (in seconds) ......................... Male Owner Time (in seconds)
106 ................................................................................................. 67
37 ................................................................................................... 50
144 ................................................................................................. 62
217 ................................................................................................. 23
211 ................................................................................................. 11
240 ................................................................................................. 41
2 ..................................................................................................... 28
111 ................................................................................................. 80
204 ................................................................................................... 2
57 .....................................................................................................

113 ..................................................................................................

79 .....................................................................................................

8 ......................................................................................................

3 .....................................................................................................

58 .....................................................................................................

73 .....................................................................................................

1. What symbol should be used for the variances of these two distributions?

2. What symbol should be used for the standard deviation of these two distributions?

3. Using the data for female owners, calculate the SS (using computation formula), and also calculate the variance, standard deviation, range, and interquartile range.

4. Using the data for male owners, calculate the SS (using computation formula), and also calculate the variance, standard deviation, range, and interquartile range.

5. Which distribution is more variable, female dog owners or male dog owners?

6. If the sample female owner data are to be used to estimate the population variance for all female dog owners, the degrees of freedom for the estimate equals __.

7. If the sample male owner data are to be used to estimate the population variance for male owners, the degrees of freedom for the estimate would be equal to ___.