In a study of academic procrastination, authors reported that for asample of 411 undergraduate students at a midsize public universitypreparing for a final exam in an introductory psychology course, themean time spent studying for the exam was 7.74 hours and the standarddeviation of study times was 3.4 hours.Construct a 95% confidence interval to estimate 4, the mean time spentstudying for the final exam for students taking introductory psychologyat this university. Interpret the interval.Note: For the purpose of this exercise, assume that it is reasonableto regard this sample as representative of students taking introductorypsychology at this university.

Given,sample size(n)=411sample mean(x¯)=7.74standard deviation(s)=3.4degrees of freedom…

Answered: In a study of academic procrastination,…

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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Intellectual development (Perry) scores were determined for 21 students in a first-year, project-based design course. (Recall that a Perry score of 1 indicates the lowest level of intellectual development, and a Perry score of 5 indicates the highest level.) The average Perry score for the 21 students was 3.27 and the standard deviation was .40. Apply the confidence interval method to estimate the true mean Perry score of all undergraduate engineering students with 90% confidence. Interpret the results.
In a survey, 22 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $38 and standard deviation of $4. Construct a confidence interval at a 90% confidence level.
A Gallup poll of 1487 adults showed that 43% of the respondents have Facebook pages. Construct a 95% confidence interval for the proportion of adults who have a Facebook page.
In a survey, 24 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $36 and standard deviation of $15. Construct a confidence interval at a 90% confidence level.
in a survey, 27 people were asked how much they spent on their child's last birthday gift. the results were roughly bell-shaped with a mean of $30 and sample standard deviation of $20. construct a confidence interval at a 95% confidence level.
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Suppose a study was conducted of community colleges in California to determine the average cost of tuition for in-state students. The study consisted of 45 community colleges from California. Based on the sample data, the average tuition was $1,440 and the standard deviation was $267. Use this information to construct and interpret a 92% confidence interval for the true average tuition of all California community colleges. Make sure to check any relevant assumptions and state how you determined whether or not they were satisfied (Be as specific as possible). Make sure to type your confidence interval in an interval format with each bound rounded to 3 decimal places [i.e. (12.345, 45.678)]
The principal at a large high school claims that students spend at least 10 hours per week doing homework, on average. To investigate this claim, an AP Statistics class selected a random sample of 250 students from their school and asked them how long they spent doing homework during the last week. The sample mean was 10.2 hours and the sample standard deviation was 4.2 hours. Construct and interpret a 95% confidence interval for the mean time that students at this school spent doing homework in the last week. Based on your interval, what can you conclude about the principal's claim? What is your t* value? Remember to use the conservative DF value.
2. University researchers claim that the average enrollment at four-year colleges is higher than two-year community colleges. Two surveys are undertaken at 35 four-year universities and 35 two-year colleges. The mean enrollment at the four-year institutions was 5,466 with a standard deviation of 8,191. The average enrollment at the two-year schools was 5,068 with a standard deviation of 4,777. Using a 95% confidence level, are the findings of the surveys consistent with the university researchers’ claim? 2. Does the null hypothesis reject H0 or fail to reject H0?
A sports news station wanted to know whether people who live in the North or the South are bigger sports fans. For its study, 121 randomly selected Southerners were surveyed and found to watch a mean of 4.6 hours of sports per week. In the North, 176 randomly selected people were surveyed and found to watch a mean of 3.2 hours of sports per week. Find a 90% confidence interval for the true difference between the mean numbers of hours of sports watched per week for the two regions if the South has a population standard deviation of 1.6 hours per week and the North has a population standard deviation of 1.4 hours per week. Let Population 1 be people who live in the South and Population 2 be people who live in the North. Round the endpoints of the interval to one decimal place, if necessary. Lower endpoint: Upper endpoint:
In a study designed to determine whether there was a cluster of brain cancer cases at a Pratt & Whitney plant, record from 223,000 employees were studied and 723 employees with brain tumors were found. Treat those employees as a random sample and construct a 95% confidence interval estimate of the proportion of all adults who develop such tumors. write a brief statement interpreting that confidence interval.

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