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Author Question: A random sample of 53 observations was taken. The average in the sample was 90 with a variance of ... (Read 114 times)

Yi-Chen

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A random sample of 53 observations was taken. The average in the sample was 90 with a variance of 400.
 a. Construct a 98 confidence interval for .
  b. Construct a 99 confidence interval for .
  c. Discuss why the 98 and 99 confidence intervals are different.
  d. What would you expect to happen to the confidence interval in Part a if the sample size was increased? Be sure to explain your answer.

Question 2

The upper and lower control limits of the proportions of defectives of a process are 0.13 and 0.07.
 a. What has been the proportion of defectives in this process?
  b. What has been the sample size?



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cloudre37

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Answer to Question 1

a. 83.41 to 96.59 (rounded)
b. 82.65 to 97.35 (rounded)
c. As the level of confidence increases, the confidence interval gets wider.
d. Get narrower because the margin of error decreased.

Answer to Question 2

a. p = 0.10
b. n = 900





 

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