Researchers want to determine if caffeine affects reaction time. They divide a sample of 150 people into 3 groups. Group 1 gets
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Answer:
A sample of 1077 is required.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is of:
42% of freshmen do not visit their counselors regularly.
This means that
98% confidence level
So , z is the value of Z that has a pvalue of
, so
.
How large of a sample size is required?
A sample size of n is required, and n is found when M = 0.035. So
Rounding up:
A sample of 1077 is required.