uick C Cafz Industry Council). What is the best point estimate of the percentage of motorcycle owners who motorcycle owners who are female: 17.5% < p < 20.6% (based on data from the Motorcycle 1. Female Motorcycle Owners Here is a 95% confidence interval estimate of the percentage of mon?
uick C Cafz Industry Council). What is the best point estimate of the percentage of motorcycle owners who motorcycle owners who are female: 17.5% < p < 20.6% (based on data from the Motorcycle 1. Female Motorcycle Owners Here is a 95% confidence interval estimate of the percentage of mon?
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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help on these with sketches would be appriciated!
Transcribed Image Text:# Understanding Confidence Intervals and Sample Size in Statistics
## 1. Female Motorcycle Owners
A 95% confidence interval estimate for the percentage of motorcycle owners who are female is given as: 17.5% < p < 20.6%, based on data from the Motorcycle Industry Council. What is the best point estimate of the percentage of motorcycle owners who are women?
## 2. Interpreting the Confidence Interval
Write a brief statement that correctly interprets the confidence interval given in Exercise 1 “Female Motorcycle Owners.”
## 3. Critical Value
For the survey described in Exercise 1 “Female Motorcycle Owners,” find the critical value used for constructing a 99% confidence interval estimate of the population proportion.
## 4. Loose Change
USA Today reported that 40% of people surveyed planned to use accumulated loose change for paying bills. The margin of error was given as ±3.1 percentage points. Identify the confidence interval that corresponds to that information.
## 5. Sample Size for Proportion
Find the sample size required to estimate the percentage of statistics students who take their statistics course online. Assume that we want 95% confidence that the proportion from the sample is within two percentage points of the true population percentage.
## 6. Sample Size for Mean
Find the sample size required to estimate the mean IQ of airline pilots. Assume that we want 99% confidence that the mean from the sample is within two IQ points of the true population mean. Also assume that σ = 15.
## 7. Requirements
A construction quality control analyst has collected a random sample of six concrete road barriers, and plans to weigh each of them to construct a 95% confidence interval estimate of the mean weight of all such barriers. What requirements must be satisfied in order to construct the confidence interval with the method from Section 7-2 that uses the t distribution?
## 8. Degrees of Freedom
In general, what does “degrees of freedom” refer to? For the sample data described in Exercise 7 “Requirements,” find the number of degrees of freedom, assuming that you want to construct a confidence interval estimate of μ using the t distribution.
## 9. Critical Value
Refer to Exercise 7 “Requirements” and assume that the requirements are satisfied. Find the critical value that would be used for constructing a 95% confidence interval estimate of μ using the t distribution.
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