Twenty-five randomly selected students were asked the number of movies they watched the previous week. The results are as follows:

# of movies Frequency

Relative Frequency

Cumulative Relative Frequency

0

5

1

9

2

6

3

4

4

1

Table 1.1 (Hint: This is a frequency table. Read the section in the textbook!)

a. Find the sample mean x = 1.48

b. Find the sample standard deviation, s = 1.12

c. Complete the columns of the chart. =

d. Find the first quartile. = 1

e. Find the median. = 1

f. Find the third quartile. = 2

g. What percent of the students saw fewer than three movies? = 80%

h. Find the 40th percentile. = 1

i. Find the 90th percentile. = 3

Exercise 2 (5 points)

I. A “random survey” was conducted of 3274 people of the “microprocessor generation” (people born since 1971, the year the microprocessor was invented). It was reported that 48% of those individuals surveyed stated that if they had $2000 to spend, they would use it for computer equipment. Also, 66% of those surveyed considered themselves relatively savvy computer users. (Source: San Jose Mercury News)

a. Do you consider the sample size large enough for a study of this type? Why or why not?

b. Based on your “gut feeling,” do you believe the percent’s accurately reflect the U.S. population for those individuals born since 1971? If not, do you think the percent’s of the population are actually higher or lower than the sample statistics? Why? Additional information: The survey was reported by Intel Corporation of individuals who visited the Los Angeles Convention Center to see the Smithsonian Institute's road show called “America’s Smithsonian.”

c. With this additional information, do you feel that all demographic and ethnic groups were equally represented at the event? Why or why not?

d. With the additional information, comment on how accurately you think the sample statistics reflect the population parameters.

Exercise 3