What changes the width of a confidence interval? A marketing director wants a 95% confidence interval for the mean cost of running shoes. She randomly samples 40 pairs of shoes and finds that the sample mean, ¯xx¯, was $122 with a sample standard deviation, ss, of $27. The marketing director concluded, with 95% confidence, that between $113.36 and $130.64 contains the mean cost of all running shoes. What would change for a wider confidence interval? Select all answers that will make the width wider. If the sample standard deviation was smaller. If the sample size decreased to 30 pairs of shoes. If the point estimate was larger. If she decreased the confidence level to a 90% confidence interval. If the point estimate was smaller. If the sample size increased to 50 pairs of shoes. If the sample standard deviation was larger. If she increased the confidence level to a 99% confidence level.
What changes the width of a confidence interval? A marketing director wants a 95% confidence interval for the mean cost of running shoes. She randomly samples 40 pairs of shoes and finds that the sample mean, ¯xx¯, was $122 with a sample standard deviation, ss, of $27. The marketing director concluded, with 95% confidence, that between $113.36 and $130.64 contains the mean cost of all running shoes. What would change for a wider confidence interval? Select all answers that will make the width wider. If the sample standard deviation was smaller. If the sample size decreased to 30 pairs of shoes. If the point estimate was larger. If she decreased the confidence level to a 90% confidence interval. If the point estimate was smaller. If the sample size increased to 50 pairs of shoes. If the sample standard deviation was larger. If she increased the confidence level to a 99% confidence level.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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What changes the width of a confidence interval?
A marketing director wants a 95% confidence interval for the
The marketing director concluded, with 95% confidence, that between $113.36 and $130.64 contains the mean cost of all running shoes.
What would change for a wider confidence interval?
Select all answers that will make the width wider.
- If the sample standard deviation was smaller.
- If the
sample size decreased to 30 pairs of shoes. - If the point estimate was larger.
- If she decreased the confidence level to a 90% confidence interval.
- If the point estimate was smaller.
- If the sample size increased to 50 pairs of shoes.
- If the sample standard deviation was larger.
- If she increased the confidence level to a 99% confidence level.
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