←An investment website can tell what devices are used to accesstheir site. The site managers wonder whether they shouldenhance the facilities for trading via smartphones so they wantto estimate the proportion of users who access the site that way.They draw a random sample of 425 investors from theircustomers. Suppose that the true proportion of smartphoneusers is 20%. Complete parts a) through c) below.a) What would the managers expect the shape of the samplingdistribution for the sample proportion to be?NonsymmetricUnimodal and symmetricSkewed to the rightSkewed to the leftb) What would be the mean of this sampling distribution?(Round to two decimal places as needed.)c) What would be the standard deviation of the samplingdistribution?Mean =Standard Deviation =needed.)(Round to three decimal places as

Answered: An investment website can tell what…

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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3. In a survey conducted recently by CNN in an attempt to find the proportion of adults that have an active account with Facebook. Among 230 females, 72% of them had an active account, while among 195 males, 60% had an active account. a. Complete the table below. Females Males X1 = X2 = n1 = n2 = b. Use the data table from above to answer the following parts: i. Find the pooled proportion P ii. Find a 95% confidence interval for the difference to the two population proportions P1 – P2 using the table from above
As Director of Student Services for the Lake County School District, you wish to estimate the proportion of families with school-aged children who would enroll in a low-cost family counseling service if such a program were available. A random sample of 50 families was polled and it was found that 35 would enroll in such a program. a. Let p represent the proportion of all families in the district who would enroll in the low-cost family counseling service. Find a point estimate for p. (Round result to 3 decimal places.) b. Find a 90% confidence interval for p. (Round results to 3 decimal places.) c. The Lake County School Board president tasks you with doing a larger study, to develop a more precise estimate. The director would like an estimate for the proportion of families who would use the low-cost family counseling service that is within 5% of the population percentage, with 90% confidence. Using the original study (described above) as a preliminary estimate for the population…
The North American Free Trade Agreement (NAFTA) enacted in 1994 is a trilateral trade agreement signed by the United States, Canada and Mexico. This trade agreement has been controversial since its inception and Americans remain split on the issue. In a Gallup Poll conducted February 1-5, 2017, 448 out of 973 randomly selected Americans aged 18 or older stated that they believed that NAFTA was bad for the United States. a. Find the point estimate for the proportion of Americans who believe that NAFTA was bad for the United States. Round your answer to 4 decimal places. b. Find the margin of error for a 95% confidence interval. Round your answer to 4 decimal places. c. Construct the 95% confidence interval for the proportion of Americans who believe that NAFTA was bad for the United States. Enter your answer as an open interval of the form (a,b) and round to 3 decimal places. d. Can you conclude that more than half of Americans believe that NAFTA was bad for the United States? No, the…
Suppose you are interested in knowing the proportion of Texas A&M students who have their own subscription to Netflix. Everyone in a class of 77 students takes a random sample of 100 Texas A&M students and asks them if they have their own Netflix subscription. Each person calculates the proportion of their sample with a subscription and we make a histogram of the 77 proportions. What kind of distribution would be displayed in that histogram? a. Population Distribution b. Sampling Distribution c. Data Distribution d. Parent Distribution e. More than one of the above
A programmer plans to develop a new software system. In planning for the operating system that he will use, hee needs to estimate the percentage of computers that use a new operating system. How many computers must be surveryed in order to be 90% confident that his estimate is in error by no more than one percentage point. Complete part (a) through (c) below. a. n= b Assummer that a recent survey suggests that about 86% of computers use a new operating system. c. Does the additional survey information from part (b) have much of an effect on the sample size that is required?
You are doing a research project in political science to determine the proportion of voters in your district who favor capital punishment. a. If no preliminary sample of voters is taken to estimate p, how large a sample is necessary to be 99% sure that the point estimate will be within a distance of .01 from p? b. The NORC found that approximately 67% of people in the U.S. favor capital punishment. How large a sample is necessary to be 99% sure that the point estimate will be within a distance of .01 from p?
4. Suppose that 15% of all students at your school ride a bicycle to class each day. Suppose further that you take a random sample of 80 students at your school. a. Is 15% number a parameter or a statistic? Explain briefly. b. Are you guaranteed that 15% of your sample ride a bicycle to class each day? Explain briefly. c. Describe the sampling distribution of the sample proportion of these 80 students who ride a bicycle to class each day. (Hint: Be sure to refer to the shape, center, and spread of this sampling distribution.) Also include a well- labeled sketch of this distribution. HCL SYstem
In a Gallup poll of 1236 adult respondents, 6% said that bad luck follows breaking a mirror. That percentage has a margin of error of 1.5 percentage points. Why is it misleading to state that the percentage is 6% with a margin of error of 1.5%?
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A researcher wants to determine the percentage of American teenagers who send or receive text messages while doing homework. Which of the following techniques would likely be the MOST efficient way of obtaining an accurate estimate for this percentage? 1. Randomly select teenagers from the list of all teenage students in every state in America and mail surveys to those teens, asking them if they send or receive text messages while doing homework. 2. Send a survey to every teenager in America and ask them if they send or receive text messages while doing homework. 3. Randomly select teenagers from the list of all teenage students in one state and mail surveys to those teens, asking them if they send or receive text messages while doing homework.
Identify the sampling techniques used in each scenario. e. surveying movie-goers as they exited the late movie, researchers determined that only young adults under the age of 22 see movies in the theater anymore.
According to the Census Bureau, the distribution by ethnic background of the New York City population in a recent year was Hispanic: 28% Black: 24% White: 35% Asian: 12% Others: 1% The manager of a large housing complex in the city wonders whether the distribution by race of the complex’s residents is consistent with the population distribution. To find out, she records data from random sample of 800 residents. The table below displays the sample data. Race Hispanic Black White Asian Others Count 212 202 270 94 22 Are these data significantly different from the city’s distribution by race? Carry out an appropriate test at the ? = 0.05 level of significance to support your answer. State the null and alternate hypotheses (write it mathematically) and write your claim. Find the test statistics. Identify the Rejection region (critical region) and fail to reject region. Show this by drawing a curve and separate the rejection region from the fail to reject region using the critical…

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