Question

A researcher is studying treatments for agoraphobia with panic disorder. The treatments are to be the...

A researcher is studying treatments for agoraphobia with panic disorder. The treatments are to be the drug Imipramine at the two doses 1.5 mg per kg of body weight and 2.5 mg per kg of body weight. There will also be a control group given a placebo. Thirty patients were randomly divided into three groups of ten each. One group was assigned to the control, and the other two groups were assigned to the two drug treatments. After twenty-four weeks on treatment, each of the subject's symptoms were evaluated through a battery of psychological tests, where high scores indicate a lessening of symptoms. Assume the data for the three groups are independent and approximately Normal with the same variance. An ANOVA F test tested the null hypothesis that there were no differences among the means for the three treatments that had a P-value less than 0.001. Which conclusion is correct?

Question 5 options:

A. No choice is correct.

B. There is strong evidence that the population mean scores for the higher dose group of 2.5 must be larger than the population mean for the lower dose group of 1.5.

C. There is strong evidence that the three population mean scores must all be different from each other because the P-value is so small.

D. There is little evidence that the three population mean scores must all be different from each other because the P-value is so small.

Options C and D were marked INCORRECT so I am trying to find the correct answer. I chose C originally so I don't understand why it's wrong. If you could explain!

Homework Answers

Answer #1

Option C would have been the right choice if the word "all" were not to be there in it. The fact that the p-value is so small implies that at least two of the three groups have significantly different means, not necessarily that all three groups have significantly different means.

Option D is wrong because with a small p-value we reject the null hypothesis of equal means.

Option B may be correct if we assume that high potency dosage (2.5 mg) leads to much better-improved symptoms than low potency dosage (1.5 mg). (But this may not be necessarily true of drugs, so can't say).

Option A, therefore, appears to be the correct choice.

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
3. Suppose you are a researcher studying treatments for depression. Imagine three treatment groups (anti-depressant, therapy,...
3. Suppose you are a researcher studying treatments for depression. Imagine three treatment groups (anti-depressant, therapy, and placebo) are being compared using Analysis of Variance. What effect would each of the following have on an F score (make it smaller, make it larger, or cause no change)? Explain why. (Note: If you have trouble, look at the slides and consider the formula F = variance between groups/variance within groups, and consider what would influence that ratio). a. A large within-group...
Researchers are studying stress and want to know if a new drug reduces feelings of chronic...
Researchers are studying stress and want to know if a new drug reduces feelings of chronic stress. They take a sample of 12 chronically stressed individuals and randomly assign them into one of three groups. The control group does not get the drug, the first experimental group gets one dose of the drug, and the second experimental group gets two doses of the drug. Then they record the number of symptoms of stress that the participants display. What can they...
1. DDT is a pesticide banned in the United States for its danger to humans and...
1. DDT is a pesticide banned in the United States for its danger to humans and animals. In an experiment on the impact of DDT, six rats were exposed to DDT poisoning and six rats were not exposed. For each rat in the experiment, a measurement of nerve sensitivity was recorded. The researchers suspected that the mean nerve sensitivity for rats exposed to DDT is greater than that for rats not poisoned. The data follow: Poisoned rats: 12.207 16.869 25.050...
A serum cholesterol level above 250 mg/dl of blood is a risk factor for cardiovascular disease...
A serum cholesterol level above 250 mg/dl of blood is a risk factor for cardiovascular disease in humans.  At a medical center in St. Louis, a study to test the effectiveness of new cholesterol-lowering drug was conducted.  One hundred people with cholesterol levels between 250 mg/dl and 300 mg/dl were available for this study.  Fifty people were assigned at random to each of two treatment groups.  One group received the standard cholesterol-lowering medication and the other group received the new drug.  After taking the drug...
1. ) Suppose a researcher is interested in the effectiveness of a new drug that is...
1. ) Suppose a researcher is interested in the effectiveness of a new drug that is intended to naturally increase hours of sleep for elderly patients experiencing insomnia above 5 hours. Suppose he collects information from a group of 64 patients, and calculates a sample mean of 6.4 hours of sleep and a standard deviation of s=0.8.   Write out your null and alternative hypotheses. Carry out the appropriate statistical test to determine if the new treatment is effective (One sided)?...
A researcher is interested in studying the effect of iron on human memory so he comes...
A researcher is interested in studying the effect of iron on human memory so he comes up with the following plan for an experiment. The experiment will involve 100 volunteers where 50 volunteers are randomly selected from all female volunteers and 50 are randomly selected from all male volunteers. Each volunteer will take a memory test 30 minutes after eating spinach. Some volunteers will be randomly assigned to eat iron-free spinach; some will eat regular spinach (with iron); others will...
When only two treatments are involved, ANOVA and the Student’s t test (Chapter 11) result in...
When only two treatments are involved, ANOVA and the Student’s t test (Chapter 11) result in the same conclusions. Also, for computed test statistics, t2 = F. To demonstrate this relationship, use the following example. Fourteen randomly selected students enrolled in a history course were divided into two groups, one consisting of 6 students who took the course in the normal lecture format. The other group of 8 students took the course as a distance course format. At the end...
Medical researchers interested in determining the relative effectiveness of two different drug treatments on people with...
Medical researchers interested in determining the relative effectiveness of two different drug treatments on people with a chronic mental illness established two independent test groups. The first group consisted of 7 people with the illness, and the second group consisted of 12 people with the illness. The first group received treatment 1 and had a mean time until remission of 199 days, with a standard deviation of 6 days. The second group received treatment 2 and had a mean time...
An experiment was done to test the effectiveness of a drug that is being considered for...
An experiment was done to test the effectiveness of a drug that is being considered for possible use in the treatment of people who experience chronic anxiety. Fifty people who are chronically anxious are identified through a local health clinic. Twenty-five people are randomly assigned to the experimental group, and they receive the new drug for six weeks. The other 25 people are randomly assigned to the control group, and they receive the commonly used drug for six weeks. After...
Do TV shows with violence and sex impair memory for commercials? To answer this question, Iowa...
Do TV shows with violence and sex impair memory for commercials? To answer this question, Iowa State researchers conducted a designed experiment in which 324 adults were randomly assigned to one of the three viewer groups of 108 participants each (Journal of Applied Psychology, June 2002). One group watched a TV program with a violent content rating (V), the second group viewed a show with a sex content rating (S), and the last group viewed a neutral TV program with...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT