Researchers are concerned about the impact of full-time college students working while they are enrolled in classes, and they would like to know if students work too much and therefore are spending less time on their classes than they should be. First, the researchers need to find out, on average, how many hours per week students are working. They know from previous studies that the standard deviation of this variable is about 5 hours. A survey of 100 full-time college students provides a sample mean of 15 hours worked per week. а. Construct a 99% confidence interval for the mean number of hours worked by full-time college students each week and briefly interpret this interval. b. Suppose another researcher is interested in constructing a 99% confidence interval for the mean number of hours worked by full-time college students each week using a sample size of 200. Find this new interval and explain to the researcher why this value is different from the one calculated in part a.

Researchers are concerned about the impact of full-time college students working while they are enrolled in classes, and they would like to know if students work too much and therefore are spending less time on their classes than they should be. First, the researchers need to find out, on average, how many hours per week students are working. They know from previous studies that the standard deviation of this variable is about 5 hours. A survey of 100 full-time college students provides a sample mean of 15 hours worked per week. а. Construct a 99% confidence interval for the mean number of hours worked by full-time college students each week and briefly interpret this interval. b. Suppose another researcher is interested in constructing a 99% confidence interval for the mean number of hours worked by full-time college students each week using a sample size of 200. Find this new interval and explain to the researcher why this value is different from the one calculated in part a.

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Solar energy is considered by many to be the energy of the future. A recent survey was taken to compare the cost of solar energy to the cost of gas or electric energy. Results of the survey revealed that the distribution of the amount of the monthly utility bill of a three-bedroom house using gas or electric energy had a mean of $117 and a standard deviation of $13. If the distribution can be considered normal: Approximately what percentage of homes will have a monthly utility bill less than $78? Note: Do NOT include the "%" sign Do NOT round any decimals, if applicable
Is it worth pursuing a doctoral degree in education if you already have an undergraduate degree? One way to help make this decision is to look at the mean incomes of these two groups. Suppose that 15 people with bachelor’s degrees in education were surveyed. Their mean annual salary was $⁢31,500 with a standard deviation of $⁢7900. Seventeen people with doctoral degrees in education were found to have a mean annual salary of $⁢47,500 with a standard deviation of $⁢6900. Assume that the population variances are not the same. Construct a 99% confidence interval to estimate the true difference between the mean salaries for people with doctoral degrees and undergraduate degrees in education. Let Population 1 be the salaries for people with doctoral degrees and Population 2 be the salaries for people with undergraduate degrees. Round the endpoints of the interval to the nearest whole number, if necessary.
Answer part c and d frq styled
1. According to one study, the average hours of sleep on a weeknight for men was 6.9 hours with a standard deviation of 1.5 hours. a. Find the proportion of men who sleep for more than 8 hours per night. b. Find the proportion of men who sleep for less than 6 hours per night. c. Find the proportion of men who sleep between 6-8 hours per night. d. Find the number of hours that represents the 90th percentile.
The mean annual incomes of certified welders are normally distributed with the mean of $50,000. The ship building association wishes to find out whether their welders earn more or less than $50,000 annually. A study conducted using 100 certified welders showed that their annual income is $50,250 with a sample standard deviation of $1050. What is the test statistic for this test? a. 2.381 b. 1.673 c. 1.367 d. 2.869
It is known that incomes from the USA follow a normal distribution with a mean of $55,000 and a standard deviation of $12,000. A researcher took a sample of 100 people in the USA and obtained a sample mean of $67,000 with a standard deviation of $18,000. What are the characteristics of the sampling distribution. A. Mean = $55,000 and Standard Deviation of the Mean = $1200 B. Mean = $55,000 and Standard Deviation of the Mean = $12000 C. Mean = $67,000 and Standard Deviation of the Mean = $569.21 D. Mean = $67,000 and Standard Deviation of the Mean = $1800
Consider the data from the Anthropology 105 class. The mean for women is 64.33 in and the standard deviation is 2.64 in. The average height of men in the US is approximately 5ft 10in. What proportion of women represented here are shorter than the average man?
Dr. Jill Biden has been teaching a seventh grade English composition class for many years. She has the feeling that over the past several years, the writing ability of students has changed. A national test of proficiency in composition was administered 5 years ago. The resulting distribution of scores was normally shaped, had a mean of 85 and a standard deviation of 10.9. In order to test his feeling, she gives her present class of 43 students the same proficiency test. The resulting mean is 80 and the standard deviation is 8.7. a. What is the alternative hypothesis? b. What is the null hypothesis? c. What is your conclusion, using an alpha of 0.05 (2 tailed). d. What type of error might you be making because of your conclusion in part c?
A recent survey of students at Regina Mundi College included a question about the number of school days each student had missed due to illness during one semester. The data are summarized below. For this data set, find Number of Frequency of days missed occurence 20 1 27 2 28 3 15 4 (a) the sample mean, (b) the sample median, and (c) the sample standard deviation.
1. The quality of the drinking water must be monitored as often as possible. One variable of concern is the pH level, which measures the alkalinity or acidity of the water. A pH below 7.0 is acidic while a pH above 7.0 is alkaline. A pH of 7.0 is neutral. A water-treatment plant is targeting higher than 8.0 pH. Based on 16 random water samples, the mean and standard deviation were found to be: Xbar=7.6 and s = 0.4. Test the claim using 5% level of significance.a. Describe the population parameter of interest.b. Formulate the null and alternativehypothesis.c. Check the assumptions.d. Choose a significance level size for a.e. Select the appropriate test statistic. Compute the test statistic using the appropriate formula.f. Establish the critical valueg. State the decision rule for rejecting or not the null hypothesis.h. Compare the computed test statistic and the critical value/s.ANSWER ALL PLEASE ASAP I WILL UPVOTE
Suppose there is a city where the mean cost per month of a one-bedroom apartment is $1,500, with a standard deviation of $250. Approximately what percentage of one-bedroom apartments in the city cost between $750 and $1,000?
In the class of 2019, more than 1.6 million students took the SAT. The distribution of scores on the math section (out of 800) is approximately normal with a mean of 528 and standard deviation of 117. What proportion of students earned scores between 500 and 600 on the SAT math test?