Investigators gave caffeine to fruit flies to see if it affected their rest. The four treatments were a control, a low caffeine dose of 1 mg/ml of blood, a medium dose of 3 mg/ml of blood, and a higher caffeine dose of 5 mg/ml of blood. Twelve fruit flies were assigned at random to the four treatments, three to each treatment, and the minutes of rest measured over a 24-hour period were recorded. Assume the data that follow are four independent SRSs (one from each of the four populations of caffeine levels) and that the distribution of the yields is Normal. A partial ANOVA table produced by Minitab follows, along with the means and standard deviation of the yields for the four groups. For this example, we notice that:
A)this is an observational study.
B)the data show evidence of a violation of the assumption that the four populations have the same standard deviation.
C)ANOVA can be used on these data because ANOVA requires the sample sizes are equal.
D)None of the answer options is correct.

Question

Investigators gave caffeine to fruit flies to see if it affected their rest. The four treatments were a control, a low caffeine dose of 1 mg/ml of blood, a medium dose of 3 mg/ml of blood, and a higher caffeine dose of 5 mg/ml of blood. Twelve fruit flies were assigned at random to the four treatments, three to each treatment, and the minutes of rest measured over a 24-hour period were recorded. Assume the data that follow are four independent SRSs (one from each of the four populations of caffeine levels) and that the distribution of the yields is Normal.  A partial ANOVA table produced by Minitab follows, along with the means and standard deviation of the yields for the four groups.  For this example, we notice that:
A)this is an observational study. 
B)the data show evidence of a violation of the assumption that the four populations have the same standard deviation. 
C)ANOVA can be used on these data because ANOVA requires the sample sizes are equal. 
D)None of the answer options is correct.

Quizplus · Accepted Answer

The Answer of Investigators gave caffeine to fruit flies to see if it affected their rest. The four treatments were a control, a low caffeine dose of 1 mg/ml of blood, a medium dose of 3 mg/ml of blood, and a higher caffeine dose of 5 mg/ml of blood. Twelve fruit flies were assigned at random to the four treatments, three to each treatment, and the minutes of rest measured over a 24-hour period were recorded. Assume the data that follow are four independent SRSs (one from each of the four populations of caffeine levels) and that the distribution of the yields is Normal.  A partial ANOVA table produced by Minitab follows, along with the means and standard deviation of the yields for the four groups.  For this example, we notice that:
A)this is an observational study. 
B)the data show evidence of a violation of the assumption that the four populations have the same standard deviation. 
C)ANOVA can be used on these data because ANOVA requires the sample sizes are equal. 
D)None of the answer options is correct.

Investigators Gave Caffeine to Fruit Flies to See If It