A student researcher compares the heights of American students and non-American students from the student body of a certain college in order to estimate thedifference in their mean heights. A random sample of 17 American students had a mean height of 70 inches with a standard deviation of 1.73 inches. A randomsample of 12 non-American students had a mean height of 66 inches with a standard deviation of 2.23 inches. Determine the 90% confidence interval for the truemean difference between the mean height of the American students and the mean height of the non-American students. Assume that the population variances areequal and that the two populations are normally distributed.Step 2 of 3: Find the margin of error to be used in constructing the confidence interval. Round your answer to six decimal places.

American students:Sample size Sample mean Sample standard deviation Non-American students:Sample…

Answered: A student researcher compares the…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 37 randomly selected people who train in groups, and finds that they run a mean of 47.7 miles per week. Assume that the population standard deviation for group runners is known to be 3.3 miles per week. She also interviews a random sample of 49 people who train on their own and finds that they run a mean of 49.4 miles per week. Assume that the population standard deviation for people who run by themselves is 4.4 miles per week. Test the claim at the 0.10 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2. Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.
A study was conducted to investigate the effect of a new drug on blood pressure. A sample of 25 patients was randomly selected and their blood pressure was measured both before and after taking the drug. The sample mean blood pressure before taking the drug was 120 mmHg and the sample mean blood pressure after taking the drug was 118 mmHg. The sample standard deviation for the blood pressure before taking the drug was 4 mmHg and the sample standard deviation for the blood pressure after taking the drug was 5 mmHg. Test the hypothesis that the average blood pressure after taking the drug is lower than the average blood pressure before taking the drug using a 0.01 level of significance.
In a recent year, a sample of the South American Redeye Piranha was collected by fishermen on a particular river. Wildlife biologists regard this sample as a random sample of all Redeye Piranha in that river. The mean length of the 60 fish in the sample was 12.88 cm, and a 99% confidence level for the true mean length of all Redeye Piranha in that river is 12.09 cm to 13.67 cm. Explain what would happen to the length of the interval if the confidence level were decreased to 95%.
The gas mileage for a certain model of car is known to have a standard deviation of 6 mi/gallon. A simple random sample of 36 cars of this model is chosen and found to have a mean gas mileage of 28.4 mi/gallon. Construct a 99% confidence interval for the mean gas mileage for this car model.
Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2. Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.
The lengths of brook trout caught in a certain Colorado stream are normally distributed with a mean of 14 inches and a standard deviation of 3 inches. What proportion of brook trout caught will be less than 18 inches in length?
A marketing researcher wants to estimate the mean amount spent ($) on a certain retail website by members of the website's premium program. A random sample of 91 members of the website's premium program who recently made a purchase on the website yielded a mean of$1700 and a standard deviation of $200. Construct a 95% confidence interval estimate for the mean spending for all shoppers who are members of the website's premium program.
Bone mineral density (BMD) is a measure of bone strength. Studies show that BMD declines after age 45. The impact of exercise may increase BMD. A random sample of 59 women between the ages of 41 and 45 with no major health problems were studied. The women were classified into one of two groups based upon their level of exercise activity: walking women and sedentary women. The 39 women who walked regularly had a mean BMD of 5.96 with a standard deviation of 1.22. The 20 women who are sedentary had a mean BMD of 4.41 with a standard deviation of 1.02. Which of the following inference procedures could be used to estimate the difference in the mean BMD for these two types of women
A recent study of 28 randomly selected employees of a company showed that the mean ofdistance they traveled to work was 14.3 miles. The standard deviation of the sample was 2.0miles. Find the 95% confidence interval of the true mean.
A sociologist found that in a sample of 45 retired men, the average number of jobs they had during theirlifetimes was 7.2. The population standard deviation is 2.3(a) Find the best point estimate of the mean.The best point estimate of the mean is
Researchers from a certain country were interested in how characteristics of the spleen of residents in their tropical environment compare to those found elsewhere in the world. The researchers randomly sampled 91 males and 109 females in their country. The mean and standard deviation of the spleen lengths for the males were 10.9 cm and 0.9 cm, respectively, and those for the females were 9.8 cm and 1.1 cm, respectively. Determine a 95% confidence interval for the difference between mean spleen lengths of males and females in this country. Click here to view page 1 of the table of critical values of t. Click here to view page 2 of the table of critical values of t. Let population 1 be all males in the country and let population 2 be all females in the country. The 95% confidence interval for µ1 - 4½ is ( | D (Round to three decimal places as needed. Use ascending order.)
The average entrance exam score of a random sample of 35 freshmen students is 89.66 with a standard deviation of 18.28. Construct a 96% confidence interval for the true mean score of the freshmen students.

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