Week 10 -Assignment

Statistics

Question 4

Explain why you should use the ANOVA instead of several t tests to evaluate mean differences when an experiment consists of three or more treatment conditions.

Solution: ANOVA is preferred because performing multiple comparisons tend to increase the overall probability of type I error (because, if each comparison has a probability \(\alpha \) of making a type I error, then the probability that at least one of the comparisons will make a type I error). On the other hand, using ANOVA the type I error is under control, no matter how many treatments are compared.

Question 5

Posttests are done after an analysis of variance.

1. What is the purpose for posttests?
2. Explain why you would not do posttests if the analysis is comparing only two treatments.
3. Explain why you would not do posttests if the decision from the ANOVA was to fail to reject the null hypothesis.

Question 16

The following summary table presents the results of an ANOVA from an experiment comparing four treatment conditions with a sample of n = 10 in each treatment. Complete all missing values in the table. (Hint: Start with the df column.)

Source SS df MS

Between treatments ____ ______ _____ F =

Within treatments 66 _______ ____

Total _____ ________

SPSS Assignment

• Enter the data for Chapter 13, question 7 into SPSS.
• State the null and alternative hypotheses.
• Conduct a one-way ANOVA test at the .05 level.
• Copy or copy object and paste relevant output from the statistical test.
• State whether or not the null hypothesis is accepted or rejected based on the results of the statistical test.

Price: $8.4

Solution: The downloadable solution consists of 4 pages, 440 words and 3 charts.
Deliverable: Word Document