2. A researcher wants to test if the mean GPAS (grade point averages) of all male and all female college studentswho are actively participate in sports are different. She took a random sample of 28 male student and 24 femalestudent who are actively involved in sports. She found the mean GPAS of the two groups to be 2.62 and 2.74,respectively, with the corresponding standard deviations equal to 0.43 and 0.38.Construct a 90% confidence interval for the difference between the two population means. Assume that the GPASof all male and all female student athletes both have normal distribution with the same standard deviation.

Answered: Image /qna-images/answer/dc69682e-3c16-4726-af90-fa7dc79f945f.jpg

Answered: 2. A researcher wants to test if 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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Several years ago, 33% of parents who had children in grades K-12 were satisfied with the quality of education the students receive. A recent poll asked 1,125 parents who have children in grades K-12 if they were satisfied with the quality of education the students receive. Of the 1,125 surveyed, 451 indicated that they were satisfied. Construct a 99% confidence interval to assess whether this represents evidence that parents' attitudes toward the quality of education have changed. What are the null and alternative hypotheses? Ho: P ▼ versus H₁: p (Round to two decimal places as needed.)
Suppose you are interested in studying regional differences in crime rates. You take a random sample of 100 cities in the South, and find a mean crime rate of 55 with a sample variance of 5.78. A sample of 100 cities in the North has a mean crime rate of 50 with a sample variance of 6.72. Construct a 95% confidence interval around the difference in crime rates between the population of Southern cities and the population of Northern cities. Interpret, in words, the meaning of this interval.
In a study of woman's bone health, a random sample of 8 women was taken, and their daily calcium intake measured. The sample mean was 926 milligrams, and the sample standard deviation was 427.2 milligrams. What is the upper limit of a 99% confidence interval for the mean daily calcium intake of all women?
A company manufactures a certain over-the-counter drug. The company samples 80 pills and finds that the mean amount of drug in the pills is 325.5 mg with a standard deviation of 10.3 mg. Find the 90% confidence interval for the mean of all the pills.
We wish to estimate what percent of 18 to 25-year old's that own a Samsung phone. Out of 400 sampled, 104 had a Samsung phone. Based on this, construct a 90% confidence interval for the proportion of all adults that own a Samsung phone.
On average, adults spend approximately 5 hours per night in NREM (non-rapid eye movement) sleep. A sleep study selects a random sample of adults and gives them each a weighted blanket. They would like to know if using the weighted blanket changes the mean number of hours per night of NREM sleep. We want to test = 5 versus ≠ 5 where = the true mean hours of NREM sleep per night for adults who use a weighted blanket. A 99% confidence interval for the true mean hours of NREM sleep per night for adults who use a weighted blanket is (5.1, 5.8) hours. Based on the confidence interval, what conclusion would you make for a test of these hypotheses? The 99% confidence interval include as a plausible value, so we would H0. We convincing evidence that the true mean hours of NREM sleep per night for adults who use a weighted blanket 5 hours.
4 - A company wants to estimate, at a 95% confidence level, the annual difference between male employees' average tardiness for work and female employees' average tardiness. For this, he randomly drew 12 from men and 10 from women. It was found that male employees' average annual tardiness time for work was 12 minutes and variance was 2 minutes, and female employees' average annual tardiness time to work was 10 minutes and variance was 3 minutes. Assuming that the population variances from which the samples are drawn are homogeneous, which of the following is the confidence interval estimate for the difference between these two population means? a) (4.6 ; 7.4) B) (0.04 ; 1.18) NS) (2.1 ; 3.2) D) (0.6 ; 3.4) TO) (1.6 ; 2.4)
A researcher wants to compare the effectiveness of two different study techniques for a test. The mean test score for the first technique is 75 with a standard deviation of 5, and the mean test score for the second technique is 80 with a standard deviation of 4. The sample size for each group is 20. What is the 95% Confidence Interval for the difference in the mean test scores for the two techniques?
Assume a researcher wants to compare the mean Alanine Aminotransferase (ALT) levels in two populations, individuals who drink alcohol and individuals who do not drink alcohol. The mean ALT levels for the individuals who do not drink alcohol is 32 with a standard deviation of 14, and 37 individuals were in the sample. The mean ALT levels for individuals who drink alcohol is 69 with a standard deviation of 19, and 38 individuals were in the sample. Construct and interpret a 95% confidence interval demonstrating the difference in means for those individuals who drink alcohol when compared to those who do not drink alcohol.
A union of restaurant and foodservice workers would like to estimate this year's mean hourly wage, u, of foodservice workers in the U.S. Last year's mean hourly wage was $8.25, and there is reason to believe that this year's value is less than last year's. The union decides to do a statistical test to see if the value has indeed decreased. The union chooses a random sample of this year's wages, computes the mean of the sample to be $7.98, and computes the standard deviation of the sample to be $1.25. Based on this information, answer the questions below. What are the null hypothesis (H) and the alternative hypothesis (H,) that should be used for the test? |Ho: u is ? H: u is ? v|? ? In the context of this test, what is a Type I error? v the hypothesis that u is ? A Type I error is ? fact, u is ? v when, in Suppose that the union decides not to reject the null hypothesis. What sort of error might it be making? ?
2. A sample of six college basketball player had an average weight of 217 pounds with a sample standard deviation of 10 pounds. Find the 95% confidence interval of the true mean weight of all basketball player.
During the nutrition research, the amount of consumed kilocalories per day was measured for 18 people - 10 women and 8 men. Results are as follows: Women: 2026, 1600, 1700, 1950, 1922, 1786, 1712, 1777, 2006, 1832; Men: 2170, 2557, 2384, 2427, 2334, 2228, 2161, 2459. Calculate a 90% confidence interval on the mean for women and men separately. Assume distribution to be normal. Round your answers to the nearest integer (e.g. 9876). Women: i Men: i

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