Statistics Chapter 10.1 Homework
Is the hypothesis test left-tailed, right-tailed, or two tailed? Right tailed What parameter is being tested? population mean
#5 Question see picture Is the hypothesis test left-tailed, right-tailed, or two tailed? What parameter is being tested?
#16 If the consequences of making a Type I error are severe, would you choose the level of significance, alpha to equal 0.01, 0.05, or 0.10?
0.01 As the level of significance, a, decreases, the probability of making a Type II error, B increases. As we decrease the probability of rejecting a true null hypothesis, we increase the probability of not rejecting the null hypothesis when the alternative hypothesis is true.
#12 The mean consumption of fruit three years ago was 98.2 pounds. A dietician believes that fruit consumption has risen since then. If we tested this hypothesis at the a=0.1 level of significance, what is the probability of committing this error?
0.1
#13 The mean score on a particular math exam is 536. A test preparation company states that the mean score of students who take its course is higher than 536. If we tested this hypothesis at the a=0.02 level, what is the probability of committing a Type 1 error?
0.2
a. two tailed b. standard deviation
10.1 #4 Question. Choose the correct answer below. left tailed right tailed two tailed What parameter is being tested?
#What type of test is being conducted in this problem? Right tailed test. What parameter is being tested? population standard deviation.
10.1 Question 3. See picture. What type of test is being conducted in this problem? What parameter is being tested?
#2 Determine whether the following statement is true or false. Sample evidence can prove that a null hypothesis is true. True or false
False
#10 Suppose the null hypothesis is rejected. State the conclusion based on the results of the test. Six years ago, 12.7% of registered births were to teenage mothers. A sociologist believes that the percentage has increased since then.
For answer see picture
#11 State the conclusion based on the results of the test. According to the Federal Housing Finance Board, the mean price of a single-family home two years ago was $299 comma 700. A real estate broker believes that because of the recent credit crunch, the mean price has decreased since then. The null hypothesis is not rejected.
For answer see picture
#9 Similar Suppose the null hypothesis is not rejected. State the conclusion based on the results of the test. Three years ago, the mean price of a single-family home was $243 comma 794 A real estate broker believes that the mean price has decreased since then.
For answer see picture
#Similar 8 Suppose the null hypothesis is rejected. State the conclusion based on the results of the test. Six years ago, 12.4% of registered births were to teenage mothers. A sociologist believes that the percentage has increased since then
For answer see picture
#9 Suppose the null hypothesis is rejected. State the conclusion based on the results of the test. Three years ago, the mean price of a single-family home was $243 comma 787 . A real estate broker believes that the mean price has increased since then.
For help me solve this see picture.
#7 a) Determine the null and alternative hypotheses, (b) explain what it would mean to make a type I error, and (c) explain what it would mean to make a type II error. Three years ago, the mean price of a single-family home was $243, 730 A real estate broker believes that the mean price has decreased since then.
For question a. see picture. b. Which of the following is a type 1 error? The broker rejects the hypothesis that he mean price is $243, 730, when it is the true mean cost. c. Which of the following is a type II error? The broker fails to reject the hypothesis that the mean price is $243,730, when the true mean price is less than $243,730
#6 a) Determine the null and alternative hypotheses, (b) explain what it would mean to make a type I error, and (c) explain what it would mean to make a type II error. Six years ago, 12.3% of registered births were to teenage mothers. A sociologist believes that the percentage has decreased since then.
For question a.) see picture. b. Which of the following is a type 1 error? The socialogist rejects the hypothesis that the percentage of births to teenage mothers is 12.3% when it is the true percentage. c. The socialist fails to reject the hypothesis that the percentage of births to teenage mothers is 12.3%, when the true percentage is less than 12.3%
#14 Five years ago, 9.6% of high school students had tried marijuana for the first time before the age of 13. A school resource officer (SRO) thinks that the proportion of high school students who have tried marijuana for the first time before the age of 13 has increased since then. (a) Determine the null and alternative hypotheses. Which of the following is correct?
For the question and answer see picture.
Answer: The probability increases. Type I and Type II errors are inversely related.
Question#17 See picture
#14 Five years ago, 9.6% of high school students had tried marijuana for the first time before the age of 13. A school resource officer (SRO) thinks that the proportion of high school students who have tried marijuana for the first time before the age of 13 has increased since then. (c) Suppose, in fact, that the proportion of high school students who have tried marijuana before the age of 13 was 9.8%. Was a type I or type II error committed?
See answer in picture.
#15 According to a report, the standard deviation of monthly cell phone bills was $6.33 three years ago. A researcher suspects that the standard deviation of monthly cell phone bills is different today. Determine the null and alternative hypotheses.
See answer in picture.
#12a The mean consumption of fruit three years ago was 98.2 pounds. A dietician believes that fruit consumption has risen since then. a) Determine the null and alternative hypotheses. Which of the following is correct?
See answer.
#8 Suppose the null hypothesis is rejected. State the conclusion based on the results of the test. Six years ago, 12.2% of registered births were to teenage mothers. A sociologist believes that the percentage has decreased since then. Is there sufficient evidence to conclude that the percentage of births is less than 12.2%?
See first picture on how to solve. Yes
#13 The mean score on a particular math exam is 536. A test preparation company states that the mean score of students who take its course is higher than 536. a.) Determine the null and alternative hypotheses.
See question and answer in picture.
#13 The mean score on a particular math exam is 536. A test preparation company states that the mean score of students who take its course is higher than 536. (d) If we wanted to decrease the probability of making a Type II error, would we need to increase or decrease the level of significance?
Since a Type 11 error can only occur when the null hypothesis is not recjected, the level of significance should be increased to make this less likely.
#1 Fill in the blanks to complete the statement. The _______________ is a statement we are trying to find evidence to support.
The alternative hypothesis is a statement we are tryiing to find evidence to support.
#13 The mean score on a particular math exam is 536. A test preparation company states that the mean score of students who take its course is higher than 536. (c) Suppose, in fact, that the mean score of students taking the prepatory course is 536. Has a Type 1 or Type II error been made?
The researcher committed a Type 1 error because he rejected the null hypothesis when the null hypothesis was true.
#12c The mean consumption of fruit three years ago was 98.2 pounds. A dietician believes that fruit consumption has risen since then. (c) Suppose, in fact, the mean consumption of fruits is 98.2 pounds. Did the researcher commit a type I or type II error?
The researcher committed a type Upper I error because he rejected the null hypothesis when it was true
#14 Five years ago, 9.6% of high school students had tried marijuana for the first time before the age of 13. A school resource officer (SRO) thinks that the proportion of high school students who have tried marijuana for the first time before the age of 13 has increased since then. (b) Suppose sample data indicate that the null hypothesis should not be rejected. State the conclusion of the researcher.
There is not sufficient evidence to conclude that the proportion of high school students has increased.
#12b The mean consumption of fruit three years ago was 98.2 pounds. A dietician believes that fruit consumption has risen since then. b) Suppose sample data indicate that the null hypothesis should be rejected. State the conclusion of the researcher. Which of the following is the conclusion that could be reached?
There is sufficient evidence to conclude that the mean consumption of fruit has risen .
#13 The mean score on a particular math exam is 536. A test preparation company states that the mean score of students who take its course is higher than 536. (b) If sample data indicate that the null hypothesis should be rejected, state the conclusion of the company. .
There is sufficient evidence to conclude that the mean score of students who take the preparation course is higher than 536.
