Improving Reading Ability

The following description is taken from the Data and Story Library (DASL).

A treatment class of 21 third-grade students participated in reading activities for eight weeks, and a control class of 23 third-graders followed the same curriculum without these activities. After the eight-week period, students in both classes took a Degree of Reading Power (DRP) test which measures the aspects of reading ability that this treatment is designed to improve.
Here are the results of the test.

Treated 24Control42
Treated 43Control43
Treated 58Control55
Treated 71Control26
Treated 43Control62
Treated 49Control37
Treated 61Control33
Treated 44Control41
Treated 67Control19
Treated 49Control54
Treated 53Control20
Treated 56Control85
Treated 59Control46
Treated 52Control10
Treated 62Control17
Treated 54Control60
Treated 57Control53
Treated 33Control42
Treated 46Control37
Treated 43Control42
Treated 57Control55
Control28
Control48
To summarize, there are 21 students who received the treatment to improve their reading level and 23 students who received no treatment at all who were in the control group. The means for the two groups were,

Control mean = 41.52
Treatment mean = 51.48

for a difference of 9.94.

What we want to know is if this difference between the two groups is significant.

Explore this question using the spreadsheet "Day 5- Means" and answer the following questions.

1. List at least two assumptions that are made about the data.

2. Develop a hypothesis about the means for the data sets. Use the spreadsheet to answer the following.

3. Change the sampling rate in cell C2 to 15 and run 30 trials. What is the percent of trials that were found to be significant?

4. Now, change the sampling rate to 25 and run 50 trials. Again, what is the percentage of trials that were significant?

Return to the Introduction.

Return to Do Your Own Analysis Page.