A sample of 20 students take Math 203 was randomly selected to evaluate the results on the Math 203 final exam. The average for the sample was 74 with a standard deviation of 7.5. Determine the 95% confidence interval for students taking the exam.  Previous studies indicate a standard deviation of 8.3.  (Assume that the population standard deviation is the 8.3.)  Assume the population is approximately normally distributed. Directions   Answer the following:       1.  Determine the type of confidence interval (z, t, or proportion).     2.  State the confidence interval.  Round your answer to 1 decimal place.     3.  Based on your confidence interval for the population (true) mean, do you feel the average is too low and the exam needs to be changed?  Explain your answer

MATLAB: An Introduction with Applications
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Author:Amos Gilat
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A sample of 20 students take Math 203 was randomly selected to evaluate the results on the Math 203 final exam. The average for the sample was 74 with a standard deviation of 7.5. Determine the 95% confidence interval for students taking the exam.  Previous studies indicate a standard deviation of 8.3.  (Assume that the population standard deviation is the 8.3.)  Assume the population is approximately normally distributed.

Directions

  Answer the following:  
    1.  Determine the type of confidence interval (z, t, or proportion).
    2.  State the confidence interval.  Round your answer to 1 decimal place.
   

3.  Based on your confidence interval for the population (true) mean, do you feel the average is too low and the exam needs to be changed?  Explain your answer 

Expert Solution
Step 1

Given information

Sample size n = 20

Sample mean = 74

Sample standard deviation s = 7.5

Population standard deviation σ = 8.3

Significance level(α) = 1 - 0.95 = 0.05

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