Chapter 9: Hypothesis Testing Basics and Errors Jonathan Hill 23% of deaths among male adults can be attributed to heart diseases. Is this percentage different . Question 1 0/1 pt 9 3 99 among residents in Sonoma County? State the Null and Alternative hypothses. Ho: ? V Select an answer V If your null and alternative hypothesis are: Ho: p = 0.36 Ha: ? V Select an answer H1:p # 0.36 Question Help: Read Video Message instructor Then the test is: Question 5 0/1 pt 9 3 99 O right tailed The p-value for a hypothesis test turns out to be 0.06045. At a 2% level of significance, what is the Oleft tailed proper decision? O two tailed O Reject Ho O Fail to reject Ho Question Help: Message instructor Question Help: Message instructor Question 2 1pt 9 1 99 . Question 6 0/1 pt 0 3 99 Answer the following True or False: The p-value for a hypothesis test turns out to be 0.01929. At a 9% level of significance, what is the A researcher hypothesizes that the average student spends less than 20% of their total study time proper decision? reading the textbook. The appropriate hypothesis test is a left tailed test for a population mean. O Reject Ho Ofalse O Fail to reject Ho O true Question Help: Message instructor Hint: Help Question 7 0/1 pt 0 3 99 For a hypothesis test, alpha = 0.05 Question Help: Message instructor The computed P-Value = 0.078 Question 3 0/1 pt 1 3 99 Should HO be rejected?: Reject H_O The average American consumes 8 liters of alcohol per year. Does the average college student consume less alcohol per year? State your null and alternative hypothesis O Fail to Reject H_0 Ho: ? V Select an answer V What is the correct conclusion? There IS sufficient evidence to reject the Null Hypothesis and accept the alternative. Ha: ? V Select an answer V There is NOT sufficient evidence to reject the Null Hypothesis and accept the alternative. Question Help: Read Video Message instructor Question Help: Message instructor Question 4 0/1 pt 5 3 99 Question 8 Pilot () 1 99_ '_...__.c.._ _, .,.._ c, . '_. ,, Food inspectors inspect samples of food products to see if they are safe, This can be thought of as a hypothesis test with the following hypotheses. Ho: the food is safe Ha: the food is not safe The following is an example of what type of error? The sample suggests that the food is safe, but it actually is not safe. type | type II not an error Question Help: 2! Message instructor 0 Question 9 I2. 0/1 pt '0 3 Q 99 A commonly cited standard for one-way length (duration) of school bus rides for elementaw school children is 30 minutes. A Local government office in a rural area conducts a study to determine if elementary schoolers in their district have a longer average one-way commute time. If they determine that the average commute time of students in their district is significantly higher than the commonly cited standard they will invest in increasing the number of school busses to help shorten commute time, What would a Type 2 error mean in this context? The local government decides that the average commute time is 30 minutes. The local government decides that the data provide convincing evidence of an average commute time higher than 30 minutes, when the true average commute time is in fact 30 minutes. The local government decides that the data do not provide convincing evidence of an average commute time higher than 30 minutes, when the true average commute time is in fact higher than 30 minutes. The local government decides that the data do not provide convincing evidence of an average commute time different than 30 minutes, when the true average commute time is in fact 30 minutes. Question Help: a Message instructor 0 Question\") 80/1 pt '03 899 Food inspectors inspect samples of food products to see if they are safe. This can be thought of as a hypothesis test with the following hypotheses. Ho: the food is safe H1: the food is not safe The following is an example of what type of error? The sample suggests that the food is not safe, but it actually is safe, type | type II not an error Question Help: 3 Message instructor 0 Question 11 Ban pt '03 399 A manufacturer of rechargeable laptop batteries markets its batteries as having, on average, 500 charges. A consumer group decides to test this claim by assessing the number of times 30 of their laptop batteries can be recharged and finds the average is 497, with a standard deviation of 10. The resulting p-value is .1111; thus, the null hypothesis is not rejected. The consumer group concludes that the manufacturer's claim that its laptop batteries can be recharged, on average, 500 times is accurate. What type of error is possible in this situation? type | type II neithe r both stion Help: 3 Message instructor 0 12 B1pt'01r399 Answer the following True or False: A researcher wants to test the hypothesis that college students weigh less on average than the average American (160 lbs). The sample mean of the 80 students who were weighed was found to be 142 pounds and the P-value was 0.03. This means that if the mean of all students' weight is 160 lbs, then there would be only a 3% chance that a randomly selected group of 80 students would have a mean weight of less than 142 lbs. false true Hint: Help Question Help: 8 Message instructor 0 Question 13 2011p: 0 3 8 99 Which of the following facts about the p-value of a test is correct? The p-value is calculated under the assumption that the null hypothesis is true. The smaller the p-value, the more evidence the data provide against H0. The p-value can have values between -1 and 1. All of the above are correct. Just (A) and (B) are correct. Question Help: E Message instructor 0 Question 14 Empt '01 B99 Suppose the results indicate that the null hypothesis should not be rejected; thus, it is possible that a type II error has been committed. Given the type of error made in this situation, what could researchers do to reduce the risk of this error? Choose a 0.01 significance level, instead of a 0.05 significance level. Increase the sample size. Question Help: 8 Message instructor 0 Question15 131p: '01 Z99 Suppose the results indicate that the null hypothesis should be rejected; thus, it is possible that a type I error has been committed. Given the type of error made in this situation, what could researchers do to reduce the risk of this error? Choose a 0.01 significance level, instead of a 0.05 significance level. Increase the sample size, Question Help: 8 Message instructor Answer the following True or False: A researcher wants to test the hypothesis that college students weigh less on average than the average American (160 lbs). The sample mean of the 30 students who were weighed was found to be 142 pounds and the P-value was 0.03. This means that if the mean of all students' weight is 160 Lbs, then there would be only a 3% chance that a randomly selected group of 80 students would have a mean weight of less than 142 lbs. false true Hint: Help Question Help: 8 Message instructor 0 Question 13 20/1 pt 03 399 Which of the following facts about the p-value of a test is correct? The p-value is calculated under the assumption that the null hypothesis is true. The smaller the p-valuey the more evidence the data provide against H0. The p-value can have values between -1 and 1. All of the above are correct. Just (A) and (B) are correct. Question Help: E Message instructor .Question14 E1pt'01399 Suppose the results indicate that the null hypothesis should not be rejected; thus, it is possible that a type II error has been committed. Given the type of error made in this situation, what could researchers do to reduce the risk of this error? Choose a 0.01 significance level, instead of a 0.05 significance level. Increase the sample size, Question Help: 8 Message instructor 0 Question15 E1pt'01899 Suppose the results indicate that the null hypothesis should be rejected; thus, it is possible that a type I error has been committed. Given the type of error made in this situation, what could researchers do to reduce the risk of this error? Choose a (101 significance level, instead of a 0.05 significance level. increase the sample size, Question Help: 8 Message instructor