Somehow I've frozen up; I don't even know where to start, please help!

1. A health psychologist investigates the number of viral infections people contract as a function of the amount of psychological stress they experience during a one-year period. She wants to see if there are significant differences (at the significance level of 0.05) in the mean number of viral infections depending on the amount of stress. She obtained the following data (N=20):

_____________________________________________________

Negligible MinimalModerateSevere

StressStressStressStress

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2247

3155

1339

1276

1468

_____________________________________________________

Please answer the following questions:

(a) What are the null and alternative hypotheses? For alternative hypothesis, present a verbal description.

(b) What assumptions should be made? Provide 4 assumptions.

(c) What are the critical values? (Specify df_between and df_within first). In addition, present the decision rules

(d) Computation: Show the process of computation as indicated in the lecture note (show the 4 stages). For Stage A, you must show the process for all items (including Items #4 and #5). Make sure to include the summary table (as shown below) as the last step:

SourceSSdfMSF

Between

WithinN/A

Total