I need an answer for the three next questions. The question in bold is the most important, please. Thanks!

1.3. State the hypothesis that we are testing in this problem: Set up the Null and Alternative.

1.3.2. If you reject, can you tell which level(s) is probably the one(s) that has the different mean? Do you think this is the result of within-group variation or between-group variation?

1.3.3. If you are suspicious of only one level, repeat the ANOVA without that level and see if you fail to reject the null in the hypothesis test.

Anova question:

Four different designs for a digital computer circuit are being studied in order to compare the amount of noise present. Determine whether the amount of noise present is the same for all four design based on the following data.

Data: