Question

“M” virus has struck (severe flu-like symptoms). Researchers randomly assigned a sample of individuals afflicted with the virus to one of three groups. Group 1 received a placebo, Group 2 received a low dose of the miracle drug “New-and-Improved Anti-M”, and Group 3 received a moderate dose of “New-and-Improved Anti-M.” Rates of recovery were recorded for each group in days, Compute the appropriate test to determine if the drug is effective.

Moderate Dose	Lo Dose	Placebo
4	8	9
3	9	8
2	8	7
3	9	12
5	6	9
4	8	6
6	9	11
3	8	5
4	9	12
6	15	9
5	6	12
5	9	7
4	10	9
7	7	8
5	9	7

• What is your computed answer?  
• What probability level did you use and why?
• What was your critical value?   
• With your computed answer, are you more likely to have made a Type I or a Type II error?

Answer 1

1. The computed answer for the quest is given below

One-way ANOVA: Y versus Factor

Source	DF	SS	MS	F	P
Factor	2	184.93	92.47	24.92	0.000
Error	42	155.87	3.71
Total	44	340.80

S = 1.926 R-Sq = 54.26% R-Sq(adj) = 52.09%
From the table the estimated test statistic value is F=24.92.

The probability level that we will use is 0.05 because it is the standard.

The critical value is F(0.05,2, 42)=3.2199.

The computed answer is F=24.92 and more than critical value 3.2199. Hence, we can conclude that at least one group has significant mean rates of recovery at the 0.05 significance level.