Practice. Testing a vaccine for HIV. Of 8198 subjects given a placebo, 74 became infected with HIV, compare with 51 of 8197 vaccinated subjects. a) Do the data support the hypothesis that the vaccination is better than a placebo in preventing HIV infection? Test at a = 0.05. b) Construct a 99% confidence interval for the difference between the proportion of the subjects that were given the placebo and the ones that were vaccinated. SE = (P1 – P2) ± z*SE n1 n2

Practice. Testing a vaccine for HIV. Of 8198 subjects given a placebo, 74 became infected with HIV, compare with 51 of 8197 vaccinated subjects. a) Do the data support the hypothesis that the vaccination is better than a placebo in preventing HIV infection? Test at a = 0.05. b) Construct a 99% confidence interval for the difference between the proportion of the subjects that were given the placebo and the ones that were vaccinated. SE = (P1 – P2) ± z*SE n1 n2

Name: Practice. Testing a vaccine for HIV. Of 8198 subjects given a placebo
Uploaded: 2024-03-20T07:07:12.000Z
Channel: Bartleby
Description: Practice. Testing a vaccine for HIV. Of 8198 subjects given a placebo, 74 became infectedwith HIV, compare with 51 of 8197 vaccinated subjects.a) Do the data support the hypothesis that the vaccination is better than a placebo in preventingHIV infec

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 beverage company would like to determine if their drink is preferred to a rival company’s drink. They perform an experiment with 150 randomly selected individuals and have them taste test the two different drinks in a controlled environment so that each person's preference is independent of others. A 90% confidence interval for the proportion preferring their drink is (0.453, 0.587). Which of the following is the correct interpretation of this confidence interval? 90% of all consumers prefer this beverage company’s drink to their rival’s between 45.3% and 58.7% of the time. We’re 90% confident that between 45.3% and 58.7% of all consumers would prefer this beverage company’s drink to their rival’s drink. We’re 90% confident that there’s a 45.3% to 58.7% chance that a randomly selected person would prefer this beverage company’s drink to their rival’s drink. We’re 90% confident that the proportion of people in the sample who prefer this beverage company’s drink over their…
A college administrator is interested in determining the proportion of students who receive some sort of financial aid. Instead of examining the records for all students, the administrator randomly draws 120 students and finds that 48 of them are receiving financial aid. Use a 90% confidence interval to estimate the true proportion of students who receive financial aid.
The dean of students at a large college is interested in learning about their opinions regarding the percentage of first-year students who should be given parking privileges in the main lot. He sends out an email survey to all students about this issue. A large number of first-year students reply but very few sophomores, juniors, and seniors reply. Based on the responses he receives, he constructs a 90% confidence interval for the true proportion of students who believe first-year students should be given parking privileges in the main lot to be (0.71, 0.79). Which of the following may have an impact on the confidence interval, but is not accounted for by the margin of error? response bias O nonresponse bias O sampling variation O undercoverage bias
2 different treatments were used to speed the relief time (in minutes) of migraines. 8 subjects received each treatment. The recovery times are listed below. Treatment 1: 20 19 29 25 34 32 39 38 Treatment 2: 18 18 16 17 29 28 21 37 Construct a 90% confidence interval for the difference in the relief time between the 2 treatments.
A survey is taken of 250 students, and a P of 0.45 is found. The same survey is repeated with 1,000 students, and the same value is found. Compare the two 95% confidence intervals. What is the relationship? Is the margin of error for the second one four times smaller? How much smaller is it?
A major company would like to assess the impact of using a professional trainer to conduct a confidence-building workshop with its salespeople. A sample of 16 workers is obtained. Half (n = 8) attend the workshop and the other half (n = 8) serve as a control group. Two weeks later, each of the participants is given a questionnaire measuring the level of self-confidence. The data are as follows: Controls Workshop M = 17.5 M = 22.7 SS = 100 SS = 124 What type of t-test would you have to conduct in this scenario? Are the data sufficient to conclude that the treatment has a significant effect? Use a two-tailed test with α = .05. State the hypothesis, find the critical region, calculate your test statistic, evaluate your hypothesis then calculate the Cohen’s d measure for this scenario. State whether this is a weak, moderate, or strong effect.
Early-childhood-development studies indicate that the more often a child is read to from birth, the earlier the child begins to read. A local parents’ group wants to test this theory and samples families with young children. They find the following results. Construct a 99% confidence interval to estimate the true difference between the proportions of children who read at an early age when they are read to frequently compared to those who were read to less often, as described in the table of results. Let Population 1 be the children who were read to frequently and Population 2 be the children who were read to less often. Round the endpoints of the interval to three decimal places, if necessary. Ages when Children Begin to Read Read to at Least Three Times per Week Read to Fewer than Three Times per Week Started Reading by age 4 60 35 Started Reading after age 4 36 51 Lower end point: Upper end point:
Ten engineering schools in the US were surveyed. the sample contains 250 electrical engineers, 80 being women; 175 chemical engineers, 40 being women. Compute a 90% confidence interval for the difference between the proportions of women in these two fields of engineering. Select one: O a. (0.02, 0.16) Ob. (0.01, 0.17] O. (0.04, 0.14) O d. [0.03, 0.15]
Suppose Z follows the standard normal distribution. Calculate the following probabilities using the ALEKS calculator. Round your responses to at least three decimal places. 0 (a) P(Z > −1.23) = = (b) P (Z ≤ 1.33) = (c) P(-1.00 < Z < 2.17) = [ S
A survey collected data on attitudes toward the quality of customer service in retail stores. The survey found that 270 of the 750 American adults sampled felt that customer service is better today than it was two years ago. We wish to develop a 94% confidence interval for the proportion of American adults who feel customer service is better today than it was two years ago. What is the population? A) the 750 American adults sampled B) customer service representatives C) all American adults
Listed below are the amounts of net worth (in millions of dollars) of the ten wealthiest celebrities in a country. Construct a 95% confidence interval. What does the result tell us about the population of all celebrities? Do the data appear to be from a normally distributed population as required? 245 210 186 168 166 163 156 156 156 156
In a survey of 900 adults, 240 said that they watched the World Cup final on television. Using these sample statistics, calculate the margin of error, E, for a 90% confidence interval for the proportion of all adults that watched the World Cup final on television. A. 0.019 B. 0.024 C. 0.029 D. 0.034