Experimental Design - ANOVA

A diaper company is considering 3 different filler materials for their
disposable diapers. Eight diapers were tested with each of the 3 filler
materials and 24 toddlers were randomly given a diaper to wear. As the
child played, fluid was injected into the diaper every 10 minutes until
the product failed (leaked). The amount of fluid (in grams) at the time
of failure was recorded for each diaper. The data are shown below.

Material 1 Material 2 Material 3

791 809 828

789 818 814

796 803 855

802 781 844

810 813 847

790 808 848

800 805 836

790 811 873







What is the response variable and what is the factor?

How many levels of the factor are being studied?

Is there any difference in the average amount of fluid the diaper can
hold using the 3 different filler materials? Is so, which ones are
different?

What is your recommendation to the company and why?

The administration of a university has been using the following
distribution to classify the ages of their students:

Age Group Estimated % of Student Population

Less than 18 2.7

18-19 29.9

20-24 53.4

Older than 24 14





A recent student survey provided the following data on age of students:

Age Group Frequency

Less than 18 6

18-19 118

20-24 102

Older than 24 26





Set up a table that compares the expected and observed frequencies for
each group.

Based on the table, do you think that the data represent the estimated
distributions?

Set up the hypotheses for the chi-square goodness of fit test.

Perform the goodness of fit test at the 0.05 level of significance.

As part of a survey on the use of Office Suites Software, the company
doing the polling wanted to know whether its population was uniformly
distributed over the following age distribution: under 25, 25 ot 44, 45
and up. The company looked at the data it had collected so far and found
the following distribution.

Age Group Estimated % of Student Population

Under 25 73

25 to 44 61

45 and up 66



Total 200



Based on the data, do you think that the respondents are uniformly
distributed over the age categories?

Set up the hypotheses to test whether the data are uniformly distributed
over the age categories.

Find the expected frequency distribution and perform the chi-square
goodness of fit test.

At the 0.05 level of significance, would you say that the respondents
were uniformly distributed over the age groups?