The human resources department of a consulting firm gives a standard creativity test to a randomly selected group of new hires every year. This year, 100 newhires took the test and scored a mean of 113.6 points with a standard deviation of 134. Last year, 95 new hires took the test and scored a mean of 116.4 pointswith a standard deviation of 16.8. Assume that the population standard deviations of the test scores of all new hires in the current year and the test socores of allnew hires last year can be estimated by the sample standard deviations, as the samples used were quite large. Construct a 90 confidence interval forthe difference between the mean test score , of new hires from the current year and the mean test score , of new hires from last year. Then tind the lowerlimit and upper limit of the 905% confidence interval.Carry your intermediate computations to at least three decimal places. Round your answeis to at least two decimal places. (If necessary, cosult a list.otfocmulas.)Lower limit: |Upper limit: 0

Givensample size(n1)=100Mean(x1)=113.6standard deviation(σ1)=13.4sample…

Answered: The human resources department of a…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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A researcher polled a sample of 1087 adults in the year 2010 , asking them how many hours per week they spent on the Internet. The sample mean was 10.49 with a standard deviation of 14.21 . A second sample of 1046 adults was taken in the year 2012 . For this sample, the mean was 9.45 with a standard deviation of 13.89 . Assume these are simple random samples from populations of adults. Can you conclude that the mean number of hours per week spent on the Internet differs between 2010 and 2012 ? Let μ1 denote the mean number of hours spent on the Internet in 2010 . Use the =α0.10 level and the P -value method with the TI-84 calculator.
The City of Calgary reports that the number of vehicles that use the Crowchild Trail bridge various on weekdays. This variation can be modeled by the Normal distribution with a mean of 107500 vehicles and a standard deviation of 8800 vehicles per day. You pick a weekday at random and set out a traffic counter on both the north-bound and south-bound lanes of the Crowchild Trail bridge. At the end of a 24-hour period, you are to download the data from the traffic counter and add the two figures to represent the total vehicle usage,X. (a) What is the probability that the total vehicle usage figure will be more than 120500 vehicles? P(X≥120500)= (b) What is the probability that the total vehicle usage figure will be between 80000 and 101000? P(80000≤X≤101000)= (c) Find the 91 percentile. That is, 91% of the time, the total number of vehicles that use the Crowchild Trail bridge in a 24-hour weekday period is at most how many? (d) 9% of the time, the total number of vehicles that use the…
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Suppose the scores on a difficult exam have a sample mean of 67 and a standard deviation of 20. Suppose the instructor decides to boost each student’s score by 10 points; that is, the instructor adds 10 points to each student’s score. What are the values of the new sample mean and sample standard deviation?
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Logan and Brian began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Logan took a test in Art History and earned a 76.8, and Brian took a test in English and earned a 68.9. Use the fact that all the students' test grades in the Art History class had a mean of 71.9 and a standard deviation of 11.6, and all the students' test grades in English had a mean of 61 and a standard deviation of 9.4 to answer the following questions.a) Calculate the z-score for Logan's test grade.z=z= [Round your answer to two decimal places.] b) Calculate the z-score for Brian's test grade.z=z= [Round your answer to two decimal places.]c) Which person did relatively better? Logan Brian They did equally well.

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