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12 Cards in this Set

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In an American criminal trial, the null hypothesis is that the defendant is not guilty. Which of the following describes a Type 2 error for a criminal trial?

A. A guilty verdict for a person who is actually innocent.
B. A not guilty verdict for a person who actually committed the crime.
C. The jury is biased.
D. No decision is reached (a "hung jury").
B. A not guilty verdict for a person who actually committed the crime.
A test to screen for a serious but curable disease is similar to hypothesis testing, with a null hypothesis of no disease, and an alternative hypothesis of disease. If the null hypothesis is rejected treatment will be given. Otherwise, it will not. Assuming the treatment does not have serious side effects, in this scenario it is better to increase the probability of:

A. making a Type 1 error, providing treatment when it is not needed.
B. making a Type 1 error, not providing treatment when it is needed.
C. making a Type 2 error, providing treatment when it is not needed.
D. making a Type 2 error, not providing treatment when it is needed.
A. making a Type 1 error, providing treatment when it is not needed.
A Statistics instructor asked a random sample of female and male students how many hours they exercise each week. Minitab output for a comparison of females and males is shown below.

What is the correct notation for the parameter that is estimated by the confidence interval (95% CI) given in the output?

A. p
B. p1 − p2
C. μ
D. μ1 − μ2
D. μ1 − μ2
A counselor wants to show that for men who are married by the time they are 30, the average age when the men are married is not 21 years old. A random sample of 10 men who were married by age 30 showed an average age at marriage of 22.2, with a sample standard deviation of 1.9 years. Assume that the age at which this population of men get married for the first time is normally distributed.

What are the appropriate null and alternative hypotheses?

A. H0: = 21 and Ha: < 21
B. H0: = 21 and Ha: >21.
C. H0: = 21 and Ha: 21.
D. H0: 21 and Ha: = 21.
C. H0: = 21 and Ha: ≠ 21.
A researcher wants to determine if the average age when women first marry has increased from 1960 to 1990. Let = average age of first marriage for women in 1990 and = average age of first marriage for women in 1960. A random sample of 10 women married in 1990 showed an average age at marriage of 24.95 years, with a sample standard deviation of 2 years. A random sample of 20 women married in 1960 showed an average age at marriage of 23.1 years, with a sample standard deviation of 1.5 years.

What are the appropriate null and alternative hypotheses?

A. H0: = 0 and Ha: 0
B. H0: 0 and Ha: = 0
C. H0: = 0 and Ha: < 0
D. H0: = 0 and Ha: > 0
D. H0: u1 - u2 = 0 and Ha: u1 - u2 > 0
In an American criminal trial, the null hypothesis is that the defendant is not guilty. Which of the following describes a Type 2 error for a criminal trial?

A. A guilty verdict for a person who is actually innocent.
B. A not guilty verdict for a person who actually committed the crime.
C. The jury is biased.
D. No decision is reached (a "hung jury").
B. A not guilty verdict for a person who actually committed the crime.
A null hypothesis is that the average pulse rate of adults is 70. For a sample of 64 adults, the average pulse rate is 71.8. A significance test is done and the p-value is 0.02. What is the most appropriate conclusion?

A. Conclude that the population average is 70.
B. Conclude that the population average is 71.8.
C. Reject the hypothesis that the population average is 70.
D. Reject the hypothesis that the sample average is 70.
C. Reject the hypothesis that the population average is 70
A test to screen for a serious but curable disease is similar to hypothesis testing, with a null hypothesis of no disease, and an alternative hypothesis of disease. If the null hypothesis is rejected treatment will be given. Otherwise, it will not. Assuming the treatment does not have serious side effects, in this scenario it is better to increase the probability of:

A. making a Type 1 error, providing treatment when it is not needed.
B. making a Type 1 error, not providing treatment when it is needed.
C. making a Type 2 error, providing treatment when it is not needed.
D. making a Type 2 error, not providing treatment when it is needed.
A. making a Type 1 error, providing treatment when it is not needed.
Which of the following examples involves paired data?

A. A psychologist compares two methods of memorizing information. Twenty people use one method and twenty other people use the second method.
B. A researcher estimates the difference between the mean forearm lengths of men and women based on a random sample of each.
C. A medical researcher measures the cholesterol levels of each of 30 heart attack patients 2 days after the attack and again 4 days after the attack.
D. A marketing research expert estimates the proportion of the 22 to 29 year-old age group that says they might buy a new car in the next two years.
C. A medical researcher measures the cholesterol levels of each of 30 heart attack patients 2 days after the attack and again 4 days after the attack.
A researcher asked random samples of 50 kindergarten teachers and 50 12th grade teachers how much money they spent out-of-pocket on school supplies in the previous school year, to see if teachers at one grade level spend more than the other. A 95% confidence interval for μ1−μ2 is $30 to $50, where μ1 and μ2 are the population means for the amounts spent by kindergarten and 12th grade teachers, respectively. Based on this result, it is reasonable to conclude that

A. 95% of all kindergarten and 12th grade teachers spend between $30 and $50 on average.
B. 95% of all kindergarten teachers spend between $30 and $50 more than 95% of all 12th grade teachers.
C. Kindergarten teachers spend more on average than do 12th grade teachers.
D. 12th grade teachers spend more on average than do kindergarten teachers.
C. Kindergarten teachers spend more on average than do 12th grade teachers.
represented by Ho is a statement that there is nothing happening
null hypothesis
represented by Ha is a statement that something is happening
alternative hypothesis