A physical therapist wants to determine the difference in the proportion of men and women who participate in regular sustained physical activity. What sample size should be obtained if she wishes the estimate to be within two percentage points with 90% confidence, assuming that (a) she uses the estimates of 21.5% male and 19.8% female from a previous year? (b) she does not use any prior estimates? (a) n= (Round up to the nearest whole number.) (b) n=(Round up to the nearest whole number.)

A physical therapist wants to determine the difference in the proportion of men and women who participate in regular sustained physical activity. What sample size should be obtained if he wishes the estimate to be within three percentage points with 95​% confidence, assuming that ​(a) he uses the estimates of 22.4​% male and 19.2​% female from a previous​ year? ​(b)he does not use any prior​ estimates? ​     (a) n= ​(Round up to the nearest whole​ number.) ​(b) n= (Round up to the nearest whole​ number.)

I only need part B

A researcher wishes to estimate the percentage of adults who support abolishing the penny. What size sample should be obtained if he wishes the estimate to be within 55 percentage points with 90​% confidence if ​(a) he uses a previous estimate of 28​%? n=what ​(b) he does not use any prior​ estimates? n=what

It is calculated that, in order to estimate the true mean amount of money spent on textbooks this semester by U of M students to within $40 with 99% confidence, we need a sample of 100 students. What sample size would be required to estimate the true mean amount of money spent on textbooks to within $10 with 99% confidence?

2. The population standard deviation for the age of Fictional College students is 8.4 years. If we want to be 95% confident that the sample mean age is within one year of the true population mean age of Fictional College students, how many randomly selected Fictional College students must be surveyed?

1.  An experimenter feels that a population standard deviation is no larger than 17.0and would like to construct a 95% two-sided t-interval for the population mean that has alength at most 2.8. What sample size would you recommend?

For each of the following settings in Exercises 2.1.1-2.1.4, (i) identify the variable(s) in the study, (ii) for each vari- able tell the type of variable (e.g., categorical and ordinal, discrete, etc.), (iii) identify the observational unit (the thing sampled), and (iv) determine the sample size. A total of 129 persons donated blood. For each of them, the blood type and cholesterol levels were recorded. 2.1.3 (a) A biologist measured the number of leaves on each of 25 plants. 2.1.1 (a) A paleontologist measured the width (in mm) of the last upper molar in 36 specimens of the extinct mam- mal Acropithecus rigidus. (b) The birthweight, date of birth, and the mother's race were recorded for each of 65 babies (b) A physician recorded the number of seizures that cach of 20 patients with severe epilepsy had during an eight-week period. 2.1.4 (a) A conservationist recorded the weather (clear, partly cloudy, cloudy, rainy) and number of cars parked at noon at a trailhead on each of 18 days.…

You are trying to determine that average height of females living in New Jersey. To estimate this population mean, you collect a sample of 100 women and the average height of the women sampled was 54.5 inches. Assume the standard deviation of the population is 3 inches. Using a 95% confidence level, determine the following:   a. Based on the poll, what is the point estimate of the mean height of female NJ residents?   b. Find the margin of error for this sample.   c. Construct a confidence interval to estimate the mean height of female NJ residents using a 95% confidence level.   d. What sample size would be required to achieve a margin of error of less than 1 inch ?

You are interested in estimating the the mean weight of the local adult population of female white-tailed deer (doe). From past data, you estimate that the standard deviation of all adult female white-tailed deer in this region to be 17 pounds. What sample size would you need to in order to estimate the mean weight of all female white-tailed deer, with a 96% confidence level, to within 7 pounds of the actual weight? Sample Size: