Question 5A 2020 survey of 1,250 American adults indicates that 77% of cell phone owners do their browsing on their phone ratherthan a computer or other device.a) Calculate a 90% confidence interval for the true proportion of Americans who access the internet on their phones,using the original sample.(i)Point estimate :(ii)90% Margin of error :(iii)90% Confidence Interval :b) Interpret the confidence interval in the context of the question.c)Suppose that you'd like to estimate the true proportion of Americans who access the internet on their cellwithin 2% with 90% confidence. How many people would you have to include in your sample? Use the mostconservative sample size.

Question 5 A 2020 survey of 1,250 American adults indicates that 77% of cell phone owners do their browsing on their phone rather than a computer or other device. a) Calculate a 90% confidence interval for the true proportion of Americans who access the internet on their phones, using the original sample. (i) Point estimate : (ii) 90% Margin of error :

Question 5 A 2020 survey of 1,250 American adults indicates that 77% of cell phone owners do their browsing on their phone rather than a computer or other device. a) Calculate a 90% confidence interval for the true proportion of Americans who access the internet on their phones, using the original sample. (i) Point estimate : (ii) 90% Margin of error :

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

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.
A random sample from a population of adults consists of 67 men and 43 women. (a) Give a 95% confidence interval for the proportion of men in the population. (b) Interpret that confidence interval.
QUESTION 23 Ali constructed a 98% confidence interval for the mean amount spent per day in a shopping mall based on 100 customers. The confidence interval was found to be (AED 1150, AED 2150). Select all correct answers. The mean amount spent per day by the 100 customers selected in the sample falls between AED 1150 and AED 2150. We are 98% confident that the mean amount spent per day by customers falls between AED 1150 and AED 2150. The mean amount spent per day by all customers falls between AED 1150 and AED 2150. 98% of all customers spent between AED 1150 and AED 2150 per day.
A computer store near campus is stocking its shelves and wants to know the relative proportions of students who use PCs vs Macs. A random sample of 60 students is surveyed, and each student is asked whether they use a PC or Mac more often. 55% select ”PC.” (a) What is the population and what is the sample in this study? (b) Calculate a 95% confidence interval for the proportion of UCI students that are PC users. (c) Provide an interpretation of this confidence interval in the context of this problem. (d) The confidence interval is pretty wide and leaves a lot of uncertainty over the proportion of UCIundergarduates who use PCs. With the goal to estimate a narrower 95% confidence interval, what is a simple change to this study that you could suggest for the next time that a similar survey is conducted?
Question 10 Express the confidence interval 21.3 % + 7.6 % in interval form. Express the answer in decimal format (do not enter as percents).
Question 82 parts A, B, and C
In a study of treatments for very painful "cluster" headaches,... Find the 90% confidence interval using technology.
QUESTION 4 Sara wants to determine the mean play time of media clips on her smartphone. A random sample of 36 media clips revealed a mean of 155 minutes and a standard deviation of 16 minutes. Find the upper confidence limit (UCL) of the 93% confidence interval estimate for the mean play time of media clips on Sara's smartphone. Round your answer to two decimal places.
Question 2 - (Please answer both a and b) A recent survey showed that from a sample of 500 packages delivered by a Postal Service, 480 were delivered on time. a) Construct a 95% confidence interval for the proportion of all packages that are delivered on time by the Postal Service. b) The manager of the Postal Services claims that 98 percent of their mail are delivered on time. Test at the 1% significance level to determine whether the true proportion is less than 98 percent.
Credit card ownership varies across age groups. Suppose that the estimated percentage of people who own at least one credit card is 64% in the 18–24 age group, 84% in the 25–34 age group, 75% in the 35–49 age group, and 77% in the 50+ age group. Suppose these estimates are based on 465 randomly selected people from each age group. (a) Construct a 95% confidence interval for the proportion of people in the 18–24 age group who own at least one credit card. (Round your answers to four decimal places.) to Construct a 95% confidence interval for the proportion of people in the 25–34 age group who own at least one credit card. (Round your answers to four decimal places.) to Construct a 95% confidence interval for the proportion of people in the 35–49 age group who own at least one credit card. (Round your answers to four decimal places.) to Construct a 95% confidence interval for the proportion of people in the 50+ age group who own at least one credit card. (Round your answers to four…
8.2 Question 3). According to the February 2008 Federal Trade Commission report on consumer fraud and identity theft, Arkansas had 1,601 complaints of identity theft out of 3,482 consumer complaints ("Consumer fraud and," 2008). Calculate a 90% confidence interval for the proportion of identity theft in Arkansas.
Suppose NBC has asked the same question to a sample of 1296 adults nine months earlier, finding 47% with an optimistic outlook for the year ahead. Develop a 95% confidence interval for the percentage of American adults who had an optimistic outlook for the economy nine months earlier.