Which of the following is an example of paired data?
a. A random sample of students is asked how much money they made during the past summer. Results for males and females are compared.
b. A randomized experiment is done in which volunteers who want to lose weight are randomly assigned to either follow a specified diet or participate in an exercise program for 6 months. At the end of the study the two groups are compared to see which one had a higher proportion of people drop out of the study.
c. An observational study is conducted on a random sample of married couples to compare the average number of hours worked per week for the husband and the wife.
d. A random sample of students is asked on the first day of the quarter how many hours they slept the night before. The question is repeated for a new random sample of students on the first day of finals week.
Q. 2A 95 confidence interval for the difference between the mean handspans of men and the mean handspans of women is determined to be 2.7 centimeters to 3.3 centimeters. Which of the following statements is the best interpretation of this interval?
a. It is likely that the difference in the population mean handspans of men and women is covered by the interval 2.7 centimeters to 3.3 centimeters.
b. It is likely that the difference in the sample mean handspans of men and women is covered by the interval 2.7 centimeters to 3.3 centimeters.
c. It is likely that if new samples of the same size were to be taken, the difference in sample means would be contained in the interval 2.7 centimeters to 3.3 centimeters.
d. It is likely that for 95 of married couples, the husband's handspan is between 2.7 and 3.3 centimeters longer than the wife's hand span.
Q. 3Which one of the following ways of collecting data would not result in paired data?
a. Each person is measured twice.
b. Similar individuals are paired prior to an experiment. Each individual in a pair receives a different treatment.
c. Two different variables are measured for each person.
d. Two independent samples are selected and the same response variable is compared between samples.
Q. 4A 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 K - 12 is 30 to 50 . 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 then 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.
Q. 5For each study, decide if the two samples are independent samples or paired samples. In an experiment, students taking French are randomly divided into two groups. Half of the students first take a written exam and a week later an oral exam. The other half of the students take the exams in reverse order. The grades of the oral exam were then compared to the grades of the written exam.
a. Independent samples
b. Paired samples
Q. 6Random samples of 200 men and 200 women were collected and their resting pulse rates were measured, to estimate how much mean resting pulse rates differ for men and women in the population. An analyst mistakenly paired the observations and constructed an approximate 95 confidence interval for the mean difference to be (5 20.2) beats per minute. If the data had been analyzed correctly, finding an approximate 95 confidence interval for the difference in population means, which of the following parts of the interval would be different?
a. The sample statistic of 5 beats per minute.
b. The multiplier of 2.
c. The standard error of 0.2.
d. None of the parts would be different; it is an equivalent analysis.
Q. 7For each study, decide if the two samples are independent samples or paired samples. A random sample of high school seniors is asked how often (times per week) they eat at a fast-food restaurant. A year later, when the students are freshmen in college, they are asked the same question. The frequencies during the senior year of high school and the freshman year in college are compared.
a. Independent samples
b. Paired samples
Q. 8A random sample of 60 mathematics majors spent an average of 200.00 for textbooks for a term, with a standard deviation of 22.50 . A random sample of 40 English majors spent an average of 180.00 for textbooks that term, with a standard deviation of 18.30 . What is the value of the pooled standard error for the difference in mean amount spent?
a. 20.93
b. 4.27
c. 16.81
d. 4.10
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