Question

In testing hypotheses, if the consequences of failing to reject a null hypothesis that is actually false are very serious, we should: A. Insist that the level of significance be smaller than the P-value Buse a very small level of significance. C. insist that the P-value be smaller than the level of significance. OD. use a very large level of significance. 1.5 QUESTION 36 A 99% confidence interval for the mean y of a population is computed from a random sample and found to be 63. We may conclude that A. there is a 99% probability that is between 3 and 9. B. there is a 99% probability that the true mean is 6, and there is a 99% chance that the true margin of error is 3. OC. It we took many, many additional random samples, and from each computed a 99% confidence interval for , approximately 90% of these intervals would contain D. All of the above 1. QUESTION 37 I collect a random sample of sizen from a population and from the data collected compute a 95% confidence interval for the mean of the population. Which approach would produce a new confidence interval with smaller width (smaller margin of error) based on these same data? O A Use a smaller confidence level. B. Use the same confidence level, but compute the interval n times. Approximately 5% of these intervals will be larger C. Use a larger confidence level D.Nothing can guarantee that you will get a smaller interval. One can only say the chance of obtaining a smaller interval is 0.05. 1.5 points QUESTION 38 A medical researcher treats 400 subjects who have high cholesterol with a new drug. The average decrease in cholesterol level is 90 mg/dl. after two months of taking the drug Assume that the decrease in cholesterol after two months of taking the drug follows a Normal distribution, with unknown mean and standard deviation a 30. Which approach would produce a confidence interval with a smaller margin of error than the 95% confidence interval you computed above? A Give the drug to only 100 subjects rather than 400, because 100 people are easier to manage and control 0. Give the drug to 500 subjects rather than 400 C. Compute a 99% confidence interval rather than a 95% confidence interval. The increase in confidence indicates that we have a better Interval None of the above 1.5 points QUESTION 30 A veterinarian collects data on the number of times race horses are raced during their career. The researcher finds the average number of moes ahore enteri 15.3 with a standard deviation of s-6.3 in a sample of n20 hores. The standard error of the sample mean is given by rounded to three digts): A 0.340 3.1.560 C.1.521 0.0.358 Save All Aw

Answer 1

36) option c)

C. If we took many, many additional random samples, and from each computed a 99% confidence interval for y, approximately 99% these intervals would contain

37) option A)

smaller CL have smaller interval width

38) increasing sample size decreases margin of error

so, answer: option B)

39)

std error= σ/√n = 6.8/√20=1.521

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