customers7(b) What is the margin of error for the confidenceinterval?(c) Interpret the confidence interval.24. You Explain It! Screen Time Michael Sullivan, the authorof this text, determined the mean amount of weekly screen timespent on his phone was 81.3 minutes. A 95% confidence intervalfor the mean amount of time spent on his phone weekly has alower bound of 72.9 minutes.(a) What is the margin of error for the confidenceinterval?(b) What is the upper bound for the confidenceinterval?(c) Interpret the confidence interval.25. Hours Worked Revisited For the "Hours Worked" surveyconducted by Gallup in Problem 21, provide tworecommendations for decreasing the width of the interval.

From the provided information, Confidence level = 95% Sample mean (x̄) = 81.3 Lower bound = 72.9

Answered: 24. You Explain It! Screen Time Michael…

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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We consider the differences between the reading and writing scores of a random sample of 200 students who took the High School and Beyond Survey. The mean and standard deviation of the differences are Xread = -0.531 and 8.858 points. write (a) Calculate a 95% confidence interval for the average difference between the reading and writing scores of all students. (Round your answers to two decimal places.) (b) Interpret this interval in context. (Round your answers to two decimal places.) We are 95% confident that on the reading test students score, on average, points lower to You may need to use the appropriate table in the Appendix of Tables to answer this question. points higher than they do on the writing test. (c) Does the confidence interval provide convincing evidence that there is a real difference in the average scores? Explain. Since 0 is included in the interval, the confidence interval does not provide convincing evidence that there is a real difference in the average scores.
A medication is undergoing a clinical trial. They have taken the blood pressure of the participants on n=25 occasions. The mean blood pressure was 132 systolic for the participants with a standard deviation of 3 points. Construct a 90% and 95% confidence interval for the true mean systolic pressure. Interpret the confidence interval in your own words. Do you think this drug is effective based on the confidence interval? Why or why not?
In a study of speed dating, male subjects were asked to rate the attractiveness of their female dates, and a sample of the results is listed below (1 = not attractive; 10 = extremely attractive). Construct a confidence interval using a 90% confidence level. What do the results tell about the mean attractiveness ratings of the population of all adult females?7,7,1,8,6,5,8,8,8,8,5,9 What is the confidence interval for the population mean u? __<u<__ (Round to one decimal place as needed.)
Step 2 (b) Which of the two intervals conveys more precise information about the value of the population proportion? Recall that a smaller standard error of results in a narrower confidence interval. A narrower confidence interval is then more precise. The width of Interval 1, (0.27, 0.35), is 0.35 0.27 = and the width of Interval 2, (0.30, 0.34), is 0.34 -0.30 = Submit Skip (you cannot come back) Therefore, --Select--- is the narrower and more precise interval.
Decide whether it describes a confidence interval for a proportion or a confidence interval for a mean. (b) Apply the correct formula to calculate the confidence interval in the format of an estimate + margin of error. During the 2016 season, Mark Williams played in 18 golf matches and used his driver club 126 times, hitting his drives an average of 278 yards per drive, with a standard deviation of 15 yards per drive. Calculate a 95% confidence interval for the distance he was able to hit his driver club in that season.
The data below were collected in a clinical trial to compare a new drug to a placebo for its effectiveness in lowering total serum cholesterol. Generate a 95% confidence interval for the difference in mean total cholesterol levels between treatments. Generate a 95% confidence interval for the proportion of all patients with total cholesterol < 200. New Drug Placebo Total Sample (n=75) (n=75) (n=150) Mean (SD) Total Serum Cholesterol 185.0 (24.5) 204.3 (21.8) 194.7 (23.2) % Patients with Total Cholesterol < 200 78.00% 65.00% 71.50% a. 95% CI ( , )
Please help with 1 a,b,c,d,e, and f.
The mean score on the math portion of the ACT for the year 2000 is μ = 20.7. A sample of 20 students in a local school district had a mean of 22.95. Using the sample, a 95% confidence interval estimate for the mean is (20.76, 25.14). State the point estimate for the mean ACT score for students. Based on this sample information , do you believe that the local students have a mean different from the general population? Why? 22.95 is in the center of the interval. The means are definitely not different. 22.95 is just outside the 95% confidence interval. Can't say the means are really different. 22.95 is not equal to 20.7. The means are definitely different. 20.7 is just outside the 95% confidence interval. Can't say the means are really different.
What happens to the interval width as confidence level increases? Why?
The Pizza Shop wanted to determine what proportion of its customers ordered only cheese pizza. Out of 80 customers surveyed, 15 ordered cheese pizza. They want a 99% confidence interval of the true proportion of customers who order only cheese pizza. What is the 99% confidence interval of the true proportion of customers who order only cheese pizza? (0.075, 0.300) (0.115, 0.260) (0.086, 0.289) (0.102, 0.273)
please please please help
State the assumptions for computing a confidence interval on the difference between means?

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