Question
help with letter C please.
ents ibrary ptions Question Help The mean and standard deviation of a random sample of n measurements are equal to 33.5 and 3.7, respectively a. Find a 90% confidence interval for Hifn. 144. b. Find a 90% confidence interval for Hifn 576. c. Find the widths of the confidence intervals found in parts a and b. What is the effect on the width of a confidence interval of quadrupling the sample size while holding the confidence coefficient fixed? a. The 90% confidence interval for H 44 is approximately 032.993.34.007 (Round to three decimal places as needed.) b. 90% confidence interval H if n is approximately (33.246.33.754 (Round to three decimal places as needed.) c. Choose the correct answer below. O A. Quadrupling the sample size while holding the confidence coefficient fixed decreases the width of the confidence interval by a factor of 4 O B. the sample size while holding the confidence coefficient fixed increases the width of the confidence interval by a factor of 2. O C. Quadrupling the sample size while holding the confidence coefficient fixed decreases the width of the confidence interval by a factor of 2. O D. Quadrupling the sample size while holding the confidence coefficient fixed increases the width of the confidence interval by a factor of 4. Quadrupling the sample size while holding the confidence coefficient fixed does not affectthe width of the confidence interval. Click to select your answer and then click Check Answer All parts showing Inco
Explanation / Answer
Width in case of part a) = 34.007 - 32.993 = 1.014
Width in case of part b) = 33.754 - 33.246 = 0.508
So,
We can see that width becomes half as we quadraple the sample size.
Option C is correct.
