A researcher has obtained the number of hours worked per week during the summer for a sample of fifteen undergraduate students.

40

25

35

28

40

20

18

30

35

38

25

15

35

33

18

Using this data set, compute the following. If necessary, round answers to the nearest hundredths (two decimal spots).

a.	mean
b.	median
c.	mode
d.	30th percentile
e.	range
f.	sample variance
g.	standard deviation