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ANOVA Problems


The situation:

Worthwhile points to consider:


Problem 1

The 24 students enrolled in PS201 in the Spring of 2000 measured immediate memory span on themselves for letters and digits per the lab project. The descriptive statistics were as follows:

Letter Span Digit Span
Mean 5.98 7.31
est sigma 0.972 1.325
n 24 24

One of the following ANOVA summary tables is appropriate to determine whether or not the independent variable was effective. I've deleted some of the values in the summary tables to help you master the relationships among the values. Fill in the missing values in both tables. Determine which is the appropriate analysis. Is there evidence digit and letter spans differ?

Candidate Summary Table 1 for ANOVA
Source SS DF MS F
Rows 1.87952899
Columns 1 25.938326
Error 18.9166667 23 0.822464377
Total 83.4791667 47 MS's don't total.

Candidate Summary Table 2 for ANOVA
Source SS DF MS F
Between 1
Within 1.350996377
Total 83.47916667 47 MS's don't total.

Problem 2

Given below are the descriptive statistics and ANOVA summary table for the Letter Span data collected by the four teams of students during Spring 2000. Again, I've deleted some of the values of the source table Excel provides. You have the information you need to complete the table. Is there evidence the independent variable was effective? Note: The entire data set is given in the Key

Descriptive Statistics for Letter Span for Volunters
Group Count Sum Average Variance
Red 18 110 6.11 1.0458
Green 18 120 6.67 0.7647
Blue 18 109.6 6.06 0.7908
Yellow 18 118.5 6.58 1.2838
Source Table for ANOVA
Source SS DF MS F
Between 3
Within 0.94628268
Total 69.7187575
MSs don't total

Key


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