# QNT351 Week5 MyStatsLab

Topics: Statistical hypothesis testing, Null hypothesis, Type I and type II errors Pages: 12 (2853 words) Published: June 29, 2015
﻿QNT/351 Week 5 My Stats Lab Answers
1. Which hypothesis, the null or the alternative, is the status-quo hypothesis? Choose the correct answer below
A. null hypothesis
B. alternative hypothesis

2. What is the level of significance of a test of hypothesis? Choose the correct answer below
A. The level of significance, β, is the probability of committing a Type II error, rejecting the null hypothesis when it is, in fact, true B. The level of significance, α, is the probability of committing a Type II error, rejecting the null hypothesis when it is, in fact, true C. The level of significance, α, is the probability of committing a Type I error, rejecting the null hypothesis when it is, in fact, true D. The level of significance, β, is the probability of committing a Type II error, not rejecting the null hypothesis when it is, in fact, false E. The level of significance, β, is the probability of committing a Type I error, rejecting the null hypothesis when it is, in fact, true F. The level of significance, α, is the probability of committing a Type I error, not rejecting the null hypothesis when it is, in fact, false

3. For each of the following rejection regions, sketch the sampling distribution for z and indicate the location of the rejection region, and determine the probability that a Type I error will be made. a. z < - 1.645 b. z > 2.575 c. z < - 1.28 or z > 1.28 d. z < - 2.33 Which sketch below shows the sampling distribution for the rejection region z < - 1.645? A. B. C.

What is the probability that a Type I error will be made for z < - 1.645? α=.05
b. Which sketch below shows the sampling distribution for the rejection region z > 2.575? A. B. C.
What is the probability that a Type I error will be made for z > 2.575? α=.005
c. Which sketch below shows the sampling distribution for the rejection region z < - 1.28 or z > 1.28? A. B. C.
What is the probability that a Type I error will be made for z < - 1.28 or z > 1.28? α=0.2
d. Which sketch below shows the sampling distribution for the rejection region z < - 2.33? A. B. C.
What is the probability that a Type I error will be made for z < - 2.33? α=.01

4. A survey found that 55% of college professors believe that their online education courses are as good as or superior to courses that use traditional face-to-face instruction. a. Give the null hypothesis for testing the claim made by the survey. b. Give the rejection region for a two tailed test conducted at α=0.10 a. What is the null hypothesis?

H0: p=.55
b. What is the rejection region? Select the correct choice below and fill in any answer boxes to complete your choice. z < - 1.645 or z > 1.645

5. A university economist conducted a study of elementary school lunch menus. During the state-mandated testing period, school lunches averaged 881 calories. The economist claimed that after the testing period ended, the average caloric content of the school lunches increased significantly. Set up the null and alternative hypothesis to test the economist’s claim. Choose the correct answer below

A. H0: µ=881, Ha: µ>881
B. H0: µ=881, Ha: µ≠881
C. H0: µ=881, Ha: µ881

6. A random sample of 100 observations from a population with standard deviation 65 yielded a sample mean of 111. Complete parts a trough c. a. Test the null hypothesis that µ=100 against the alternative hypothesis that µ>100, using α=0.05. Interpret the results of the test. A. H0 is rejected

B. H0 is not rejected
Interpret the results of the test. Choose the correct interpretation below A. There is sufficient evidence to indicate the true population mean is greater than 100 at α=0.05 B. There is sufficient evidence to indicate the true population mean is smaller than 100 at α=0.05 C. There is sufficient evidence to indicate the true population mean is not equal to 100 at α=0.05 b. Test the null...