An investigator conducts an experiment involving the effects of three levels of a drug on memory. Subjects are randomly assigned to one of three conditions. A different drug level is administered in each condition. Memory is measured 10 minutes after each subject receives the drug. The following scores are recorded. The higher the score, the better the memory. Using a = 0.05, what do you conclude?
A) reject H 0 ; the drug has the same effect on memory at all levels
B) reject H 0 ; the drug does not have the same effect on memory at all levels
C) retain H 0 ; we cannot conclude that the drug affects memory
D) accept H 0 ; the drug has no effect on memory

Question

An investigator conducts an experiment involving the effects of three levels of a drug on memory. Subjects are randomly assigned to one of three conditions. A different drug level is administered in each condition. Memory is measured 10 minutes after each subject receives the drug. The following scores are recorded. The higher the score, the better the memory.  Using a = 0.05, what do you conclude?
A) reject H 0 ; the drug has the same effect on memory at all levels 
B) reject H 0 ; the drug does not have the same effect on memory at all levels 
C) retain H 0 ; we cannot conclude that the drug affects memory 
D) accept H 0 ; the drug has no effect on memory

Quizplus · Accepted Answer

We need to conduct a one-way ANOVA test to determine if there are any significant differences in memory scores between the three levels of drugs. Running the ANOVA test gives us a p-value of 0.017, which is less than our significance level of 0.05. Therefore, we reject the null hypothesis that the drug has the same effect on memory at all levels and conclude that the drug does not have the same effect on memory at all levels. Choice B is the correct answer.

An Investigator Conducts an Experiment Involving the Effects of Three