Evaluate the standard deviation

Reference no: EM137738

1. A researcher wishes to compare the effect of two stepping heights (low and high) on heartrate in a step-aerobics workout. A collection of 50 adult volunteers was randomly divided into two groups of 25 subjects each. Group 1 did a standard step-aerobics workout at the low height. The mean heartrate at the end of the workout group 1 was 1 = 90.00 beats per minute with a standard deviation s₁ = 9 beats per minute. Group 2 did the same workout but at the high step height. The mean heart-rate at the end of the workout for the subjects in group 2 was 2 = 95.08 beats per minute with a standard deviation s₂ = 12 beats per minute. Assume the two groups are independent and the data are approximately Normal. Let µ₁ and µ₂ represent the mean heart rates we would observe for the entire population if all members of this population did the workout using the low or high step height, respectively. Suppose the researcher had wished to test the hypotheses H₀: µ₁ = µ₂, H a: µ₁ < µ₂. The P-value for the test is (use the conservative value for the degrees of freedom)

A. larger than 0.10.
B. between 0.10 and 0.05.
C. between 0.05 and 0.01.

2. A sportswriter wishes to see if a football filled with helium travels farther, on average, than a football filled with air. To test this theory, the writer uses 18 adult male subjects, randomly divided into two groups of 9 subjects each. Group 1 kicked a football filled with helium to the recommended pressure. Group 2 kicked a football filled with air to the recommended pressure. The mean yardage for group 1 was 1 = 30 yards, with a standard deviation s1 = 8 yards. The mean yardage for group 2 was 2 = 26 yards, with a standard deviation s2 = 6 yards. Assume the two groups of kicks are independent. Let µ₁ and µ₂ represent the mean yardage observed for the entire population if all members of the population kicked, respectively, a helium- and air-filled football. Assuming two-sample t procedures are safe to use, a 90% confidence interval for µ₁ - µ₂ is (use the conservative value for the degrees of freedom)

A. 4 ± 5.5 yards.
B. 4 ± 6.2 yards.
C. 4 ± 7.7 yards.

Reference no: EM137738

Questions Cloud

Difference between the t and z distributions : The correct set of hypotheses to test the effect of the bonus plan, the difference between the t and z distributions

Evaluate the standard error for the sample : The standard deviation of grade points was 0.65 and the mean was 2.89. The standard error for the sample was

Evaluate the confidence interval : The 50 members of the placebo group had blood pressure lowered by an average of 15 points with standard deviation 8 points. To analyze this information we will use a, When testing whether or not the increases in spending are different, the test is ..

Water displacement method : Each egg was also measured for volume using a water displacement method. We wanted to know if the two methods agreed or not

Evaluate the standard deviation : Evaluate the standard deviation - use the conservative value for the degrees of freedom, Assume the two groups are independent and the data are approximately Normal. Let µ 1 and µ 2 represent the mean heart rates we would observe for the entire po..

Standard deviations for first- and second-time : Standard deviations for first- and second-time and confidence interval

Test the hypotheses : The sample size n, the sample means, and the sample standard deviations for the two groups are given

Confidence interval : Do students tend to improve their SAT Mathematics (SAT-M) score the second time they take the test? A random sample of four students who took the test twice received the following scores

What conclusion can be made from this study : It has been claimed that women live longer than men; however, men tend to be older than their wives. Ages of sixteen husbands and wives from England were obtained. The null hypothesis of equality of means is rejected. What conclusion can be made f..

User Account

All Pages