The University is considering changing the email system that they currently use. Since there are substantial learning costs associated with any new software, the University only wants to change to the new system if it is very confident that there is at least a 20% difference in the proportion of faculty and staff who say they like the new system. In a sample of 139 users of the current system, the University finds that 66 say they like the current system. In another sample of 92 experimental users of the “new” system, the University finds that 73 of them like the new system. When testing the hypothesis (using a 5% level of significance) that there is at least a 20% difference in the proportion of users who like the two systems, what is the test statistic? (please round your answer to 2 decimal places)

Motivational speakers want to be perceived as trustworthy. One hypothesis is that speakers who exhibit immediacy behaviors such as making eye contact, smiling and leaning forward might be perceived as more trustworthy than those who do not engage in these behaviors. To test this hypothesis, a psychologist obtained data from 26 participants. For people in a non-immediacy group, the speaker did not engage in any immediacy behaviors. For the immediacy group, however, the speaker made eye contact, smiled and leaned forward while giving a speech. After the speech, participants rated the speaker on a scale of trustworthiness ranging from 1 (not at all trustworthy) to 9 (highly trustworthy). The following data were obtained. Test whether the immediacy behaviors of the speaker affect trustworthiness rating.   No immediacy behavior Immediacy behavior 4 4 7 4 5 3 6 5 3 5 9 8 4 6 8 7 6 3 8 6 7 5 7 8 7   6…

Applicants for temporary office work at Carter Temporary Help Agency who have successfully completed an administrative assistant course are then placed in suitable positions by Nancy Dwyer and Darla Newberg. Employers who hire temporary help through the agency return a card indicating satisfaction or dissatisfaction with the work performance of those hired. From past experience it is known that 75% of the employees placed by Nancy are rated as satisfactory, and 65% of those placed by Darla are rated as satisfactory. Darla places 60% of the temporary office help at the agency, and Nancy places the remaining 40%. If a Carter office worker is rated unsatisfactory, what is the probability that he or she was placed by Darla? (Round your answer to three decimal places.)

A researcher conducts an experiment to test whether memory changes with age. They recruited 24 participants separated into four age  groups. The groups differ according to the age of subjects. In group one, all participants are 30 years old. Group 2, 40 years old. Group 3, 50 years old. And group 4, 60 years old. Assume that the participants are all in good health and that the groups are matched on other important variables  such as years of education, IQ, gender, motivation, and so on. Each participant is shown a series of nonsense syllables ( a meaningless combination of three letters such as Daf or FUM ) at a rate of one syllable every four seconds. The series is shown twice, after which participants are asked to write down as many of the syllables as they can remember. Below is number of syllables remembered by each participant. 30 years old 14 13 15 17 12 10 40 years old 12 15 16 11 12 18 50 years old 17  14 14 9 13 15 60 years old 13 10 7 8 6 9 what is the alternative and null…

A report described a survey of parents of children under the age of 18. Each person in a representative sample of 838 working fathers and a sample of 595 working mothers was asked if balancing the responsibilities of a job and a family was difficult. It was reported that 437 of the fathers surveyed and 364 of the mothers surveyed said that it was difficult. The two samples were independently selected and were thought to be representative of working fathers and mothers of children under 18 years old. USE SALT Use this information to calculate a 95% confidence interval estimate of the difference between the proportion of working fathers who find balancing work and family difficult, p₁, and this proportion for working mothers, P2. (Use a statistical computer package to calculate the P-value. Use P₁ - P₂. Round your answers to three decimal places.) to Interpret the interval. O There is a 95% chance that the true difference between the proportion of working fathers who find balancing work…

People who experience online harassment either ignore it or respond via postings or involving authorities. Is one method more effective than the other? A 2014 Pew Research Center report, based on a random sample of American adults, found that 412 of the 549 respondents who had chosen to ignore online harassment thought that it was an effective way to deal with the issue. Of the 368 respondents who had chosen to respond to online harassment, 305 thought that it had been effective.

An apartment management company wants to explore the consequences of allowing residents to have multiple dogs. They would like to find out whether the number of dogs predicts resident ratings. They would also like to control for the year the apartment complex was built because that might also affect the resident rating. They have collected data on several of their existing complexes. For each complex, they have counted the number of dogs currently living in the complex, the year the complex was built, and the average rating for that particular complex. They would like to perform a multiple regression on these variables to predict resident ratings. See data below. These data are the same as the previous question.  Positive and Negative Dog Ratings Number of dogs Year of facility Rating (out of 5) 54 1975 2 31 1964 3.5 0 2015 4.8 11 2011 3.8 73 1964 2.3 23 2016 3.7 0 2015 4.7 49 1989 2.7 What can we conclude about this multiple regression analysis? Fill in the…

The Women’s Institutional Studies group at a Midwestern university wanted to compare the percentages of female faculty members in the various units on campus in Spring 2004.  Of particular interest were the percentages of female faculty in the College of Education and in the College of Business .  In a sample of 80 College of Education faculties, there were 36 females, and in a sample of 70 College of Business faculties, there were 15 females.  Based upon this sample information, which of the following is the 98% confidence interval for the difference in the actual percentages of female faculty between College of Education and College of Business ?   a. (0.075, 0.405).   b. (0.123, 0.357).   c. (-0.012, 0.252).   d. (0.058, 0.422).   e. (0.101, 0.379).

Exercise is known to produce positive psychological effects. Interestingly, not all exercise is equally effective. It turns out that exercising in a natural environment (e.g., jogging in the woods) produces better psychological outcomes than exercising in urban environments or in homes (Mackay & Neill, 2010). Suppose that a sports psychologist is interested in testing whether there is a difference between exercise in nature and exercise in the lab with respect to post-exercise anxiety levels. The researcher recruits n 5 7 participants who exercise in the lab and exercise on a nature trail. The data below represent the anxiety scores that were measured after each exercise session.   Treat the data as if the scores are from an independent-measures study using two separate samples, each with n 5 7 participants. Compute the pooled variance, the estimated standard error for the mean difference, and the independent-measures t statistic. Using a 5 .05, is there a significant difference…

A survey was conducted of two types of marketers. The first type being marketers that focus primarily on attracting business (B2B), and the second type being marketers that primarily target consumers (B2C). It was reported that 518 (88%) of B2B and 250 (61%) of B2C marketers commonly use a business social media tool. The study also revealed that 313 (53%) of B2B marketers and 243 (60%) of B2C marketers commonly use a video social media tool. Suppose the survey was based on 589 B2B marketers and 407 B2C marketers. Complete parts (a) through (c) below. a. At the 0.05 level of significance, is there evidence of a difference between B2B marketers and B2C marketers in the proportion that commonly use the business social media tool? Let population 1 correspond to B2B marketers and population 2 correspond to B2C marketers. Choose the correct null and alternative hypotheses below. O A. Ho: T1 2 T2 B. Ho: T STh2 H1: Tq T2 C. Ho: Tq # T2 H1: Tq = T2 O D. Ho: T4 = T2 Determine the test…