I need someone with a highly educated mind to consider this question?

Question

Consider a study with 30 subjects who are told they will be involved in a study on the effects of caffiene and sleep. They are randomly chosen to be given a caffiene pill or a placebo. The report of the study claims that caffiene has no effect on the amount of sleep a person is able to get. Do you think this conclusion is likely to be justified based on the study as described? Explain why or why not. (Assume all aspects of the study were conducted properly.)

Answer 1

The lack of positive results should not be misconstrued to make an affirmative statement. Therefore, if the report was not worded very carefully, they would run the risk of making claims that are not actually based on the data. (There was no evidence that caffeine affected sleep patterns, but that is distinct from evidence that caffeine does *not* affect sleep patterns.)

If *all* aspects of the test were done correctly, then the study's conclusion will be valid so long as the study's conclusion addresses the actual research appropriately. This is a tautology.

Since you said that all aspects of the study were conducted properly, I am assuming that their report of the study was conducted properly, too. This means reporting the results in such a way that the emphasis is on the small sample size. "No effect on sleep patterns were found using X criteria in this group of 30 people." You would need to look at other statistics to ensure that the two groups were not different from each other in a significant way, which is unlikely in such a small group.

Of course, before making recommendations, one would want to gather a much larger sample. A sample size of 15 in each group lacks to power to allow you to stratify across different subgroups (sex, age, etc.).

Answer 2

"As described" I see some problems, neither the dose or time the dose is given are specified. For example, if the dose was 10mg (about 1/10 of what is in a cup of coffee), first thing in the morning, I would not expect to see much effect on sleep.

Then there is the issue of statistics, which is not my field of expertise, the sample does seem a little small to me, for something as complex and variable as a human.

You do complicate the question by saying "(Assume all aspects of the study were conducted properly.)" so maybe the the dose and time is considered, but that is not explicitly stated. If one "assume[s] all aspects of the study were conducted properly" then I suppose the the conclusion is likely to be justified, (barring problems with the sample size) but ones confidence in "conducted properly" will be directly related to one's confidence in the conclusion.

I just realized, probably the main point of the question is; since the subjects are told what the study is about does the placebo effect skew the results? I'd think that is likely, or at least the possibility needs to be considered, so the conclusions would be suspect, and most of the time i spent writing this was wasted.

Answer 3

The report was conducted to determine whether Caffeine can affect one's sleep pattern. For the 30 subjects mentioned, it is not clear as to how many were given the caffeine and how many were put on the placebo, so then what pattern will the experiment take? There has to be a clear demarcation as to control the experiment using the placebo group as a constant and then the Caffeine group can be clearly observed as to whether their sleep pattern will change significantly or not. Hence, this conclusion that Caffeine has no effect on the "amount" of sleep a person is able to get is not justified based on the study "conducted".

Answer 4

1. The group is too small.
2. Another control group should have been told the caffeine and placebo were sleep aids.
3. How was the amount of sleep measured? Was it opinion?
4. How many of the subjects were caffeine tolerant?
5. How many were caffeine intolerant?
6. What are the ages of the subjects?
7. What are the sexes of the subjects?
8. Did any subjects suffer from ADHD or narcolepsy?
9. Where did the subjects sleep?
10. What are the races and ethnicities of the subjects? (Some religious sects prohibit the use of caffeine in any form.)
You may have gathered by now that I think the study invalid because it is too simplistic, and omits a multitude of variables.

Answer 5

Though all aspects of the study were conducted properly, the result is going to be less reliable. The reasons are
1. Seeing the nature of study, its highly likely that the subjects may get little anxious and mentally more/less active. Even if they take placebo its likely that they remain in either more or less active mental state than they should b normally. And in this study mental activity plays most important role.
2. The better way would have been if the test was done "double blind"., where the subjects and doctors both are unaware of the test and its result. This rules out the subjective error on doctor's part in evaluating the effect of caffiene and the effect of anxiety and additional mental alertness on subject's part.

Answer 6

This study is fatally flawed because of improper controls and experimenter bias. By telling the subjects they will get caffeine there will be a strong placebo effect. They need to be told nothing that will bias subject behaviour. Also the sample size is too small. There are statistical tests that can approximate the number of subjects needed.

Answer 7

Sample size too small and depends if the sample was already used to caffeine in which case they would have lesser impact.
In my case I dont get good sleep if I take caffeine before sleeping.

Answer 8

Smaple size is too small. It also depends on their age. In my case i'm 18 yrs. old and caffeine has no effect on me.