Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit

STA 2023

Written Homework #5

This assignment is due at 11:59 pm (Beijing time) on the date listed on Moodle but you should work on it throughout the week as you finish each Section (the questions are labeled by Section number). Write all work on separate paper,scan, and submit the assignment to Moodle. Be sure to show all steps for full credit.

1. Section 7.1

In a survey of 1002 people, 70% said that they voted in a recent presidential election. Voting records show that 61% of eligible voters actually did vote.

(a)  Find a 98% confidence interval estimate of the proportion of people who say that they voted. Write this solution as a sentence.

(b) Are the survey results consistent with the actual voter turnout? Why or why not?

2. Section 7.2

Assume that all grade-point averages are to be standardized on a scale between 0 and 4. How many grade-point averages must be obtained so that the sample mean is within 0.1 of the population mean? Assume that a 95%

confidence level is desired. Note: If we use the Range Rule of Thumb, we can get an estimate of σ the range divided by 4, or σ  = 1. Does the sample size seem practice?

3. Section 8.1

Use asignificance level of a  = 0.05 and the following information to write the conclusion sentence of the hypothesis test:

Original Claim: More than 58% of adults would erase all of their personal information online if they could. The hypothesis test results in a P-value of 0.0257.

For Questions #4 & 5, you may assume all requirements for the needed test have been satisfied. Please show all five steps of the hypothesis testing process (as shown in the lecture videos & PowerPoints).

4. Section 8.2

A drug company provides a “1-Panel-THC” test for marijuana usage. Among 300 subjects tested, results from 27    subjects were wrong (either a false positive or a false negative). Use a 0.05 significance level to test the claim that less than 10% of the test results are wrong. Does the test appear to be good for most purposes?

5. Section 8.3

A set of data about several years of earthquake depths hasn = 600,   ̅(x) = 5.82 km, and S  = 4.93 km. Use a 0.01 significance level to test the claim of a seismologist that these earthquakes are from a population with a mean   depth equal to 5.00 km.