
A First Course in Probability (10th Edition)
10th Edition
ISBN: 9780134753119
Author: Sheldon Ross
Publisher: PEARSON
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A marketing researcher wants to find 95% confidence interval for the
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- Russell is doing some research before buying his first house. He is looking at two different areas of the city, and he wants to know if there is a significant difference between the mean prices of homes in the two areas. For the 39 homes he samples in the first area, the mean home price is $176,400. Public records indicate that home prices in the first area have a population standard deviation of $32,930. For the 32 homes he samples in the second area, the mean home price is $181,500. Again, public records show that home prices in the second area have a population standard deviation of $23,835. Let Population 1 be homes in the first area and Population 2 be homes in the second area. Construct a 95% confidence interval for the true difference between the mean home prices in the two areas. Round the endpoints of the interval to the nearest whole number, if necessary. Lowest Endpoint = upper Endpoint=arrow_forwardYou hypothesize that people in stats classes are happier than people in all other classes. You compare happiness scores in three of your classes: Statistics, Developmental Psychology, and Social Psychology. In Statistics there are 15 students and the mean happiness rating is 23.1 with a standard deviation of 9.78. In Developmental Psychology there are 15 students and the mean happiness rating is 24.4 with a standard deviation of 2.92. In Social Psychology there are 15 students with a mean rating of 17.7 and standard deviation of 8.46. The sum of squares between groups is equal to 384. The sum of squares within groups is equal to 2461. Use the One-Way ANOVA calculation table to help calculate. What is the degrees of freedom within samples?arrow_forwardRachael and Autumn began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Rachael took a test in English and earned a 81.8, and Autumn took a test in Math and earned a 63.6. Use the fact that all the students' test grades in the English class had a mean of 71.3 and a standard deviation of 11.4, and all the students' test grades in Math had a mean of 60.2 and a standard deviation of 8.3 to answer the following questions. a) Calculate the z-score for Rachael's test grade.z=z= b) Calculate the z-score for Autumn's test grade.z=z= c) Which person did relatively better? RachaelAutumnThey did equally well.arrow_forward
- A psychologist is studying the self image of smokers, as measured by the self-image (SI) score from a personality inventory. She would like to examine the mean SI score, μ, for the population of all smokers. Previously published studies have indicated that the mean SI score for the population of all smokers is 82and that the standard deviation is 12, but the psychologist believes that the value for the mean has decreased. She plans to perform a statistical test. She takes a random sample of SI scores for smokers and computes the sample mean to be 7.Based on this information, answer the questions below. What are the null hypothesis (H0) and the alternative hypothesis (H1) that should be used for the test?H0: μ is ?less than less than or equal togreater thangreater than or equal to not equal toequal to ? 82 74 12 H1: μ is ?less thanless than or equal togreater thangreater than or equal tonot equal toequal to ? 82 74 12 In the context of this test, what is a Type II error?A Type…arrow_forwardMario's weekly poker winnings have a mean of $353 and a standard deviation of $67. Last week he won $185. How many standard deviations from the mean is that?arrow_forwardA psychologist is studying the self image of smokers, as measured by the self-image (SI) score from a personality inventory. She would like to examine the mean SI score, μ , for the population of all smokers. Previously published studies have indicated that the mean SI score for the population of all smokers is 80 and that the standard deviation is 12 , but the psychologist believes that the value for the mean has decreased. She plans to perform a statistical test. She takes a random sample of SI scores for smokers and computes the sample mean to be 74 . Based on this information, answer the questions below. What are the null hypothesis ( H0 ) and the alternative hypothesis ( H1 ) that should be used for the test? H0 : μ is ?less thanless than or equal togreater thangreater than or equal tonot equal toequal to ?748012 H1 : μ is ?less thanless than or equal togreater thangreater than or equal tonot equal toequal to ?748012In the…arrow_forward
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