Question

You are interested in the time students usually spend studying for the final exams. Assume that...

You are interested in the time students usually spend studying for the final exams. Assume that the total study time during the final week in the semester among students is approximately Normally distributed with mean= 12 hours and a standard deviation = 4.4 hours . You initially plan to take a simple random sample of size n=50 and compute the average total study time.

  1. What is the standard deviation for the average studying time in hours?
  2. Imagine you sample 50 students and calculate an average of hours. Calculate the 95% Confidence Interval.
  3. Calculate the 80% Confidence Interval.
  4. You want to use a sample size such that the margin of error for the 95% CI only is hours. Should the sample size be larger or smaller than 50. Briefly explain.  
Math   Statistics-And-Probability   
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Answer #1

The standard deviation for the average studying time in hours is

The 95% confidence interval for the average studying time is given by

The 80% confidence interval for the average studying time in hours is

Thank You!! Please Upvote!!

[In the last question, data is not given, i.e. the margin of error in hours is not specified.]

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