In her book Red Ink Behaviors, Jean Hollands reports on the assessment of leading Silicon Valley companies regarding a manager's lost time due to inappropriate behavior of employees. Consider the following independent random variables. The first variable x1 measures manager's hours per week lost due to hot tempers, flaming e-mails, and general unproductive tensions. x1: 3 5 8 2 2 4 10 The variable x2 measures manager's hours per week lost due to disputes regarding technical workers' superior attitudes that their colleagues are "dumb and dispensable". x2: 8 5 4 9 9 4 10 3 (i) Use a calculator with sample mean and sample standard deviation keys to calculate x1, s1, x2, and s2. (Round your answers to two decimal places.) x1 = s1 = x2 = s2 = (ii) Does the information indicate that the population mean time lost due to hot tempers is different (either way) from population mean time lost due to disputes arising from technical workers' superior attitudes? Use α = 0.05. Assume that the two lost-time population distributions are mound-shaped and symmetric. (a) What is the level of significance? What is the value of the sample test statistic? (Test the difference μ1 − μ2. Do not use rounded values. Round your final answer to three decimal places.)

Mike Jimenez is president of the teachers’ union for Preston School District. In preparing for upcoming negotiations, he would like to investigate the salary structure of classroom teachers in the district. He believes there are three factors that affect a teacher’s salary: years of experience, a rating of teaching effectiveness given by the principal, and whether the teacher has a master’s degree (0 = No, 1 = Yes). A random sample of 20 teachers resulted in the following data.   Salary ($ Thousands) Years of Experience Principal's Rating Master's Degree 51.1 8 95 0 43.6 5 84 0 39.3 2 100 1 53 15 51 1 48.6 11 53 0 55 14 81 1 52 9 85 0 46.8 7 52 1 58.6 22 68 1 41.7 3 97 1 35.7 1 83 0 40.6 5 71 0 61.8 23 77 1 46.7 17 61 0 48.4 12 83 1 43.6 14 71 0 51.8 8 59 1 40.7 4 93 0 42.8 2 58 1 42.9 8 90 0   a. What is the question being asked?      b. Label your dependent variable: y =     c. Label your independent variables: x1 =  x2 =  x3 =    d.…

Tourism is extremely important to the economy of Florida. Hotel occupancy is an often-reported measure of visitor volume and visitor activity (Orlando Sentinel, May 19, 2018). Hotel occupancy data for February in two consecutive years are as follows. Current Year Previous Year Occupied Rooms 1,435 1,501 Total Rooms 1,750 1,900 a. Formulate the hypothesis test that can be used to determine whether there has been an increase in the proportion of rooms occupied over the one-year period. Let pi = population proportion of rooms occupied for current year P2 = population proportion of rooms occupied for previous year Ho : P1 – P2 less than or equal to 0 Ha : Pi – P2 greater than 0 b. What is the estimated proportion of hotel rooms occupied each year (to 2 decimals)? Current year Previous Year c. Conduct a hypothesis test. What is the p-value (to 4 decimals)? Use Table 1 from Appendix B. p-value

Some researchers have noted that adolescents who spend a lot of time playing video or computer games are at greater risk for depression and violence. This is an example of:   a. an observational study with lurking variables that may explain the association.   b. a paired data experiment, because we are studying both aggression and game playing.   c. a single-blind experiment, because the subjects knew they were playing games.   d. a valid conclusion, because more time yields more aggression is a positive association.

The Bureau of Labor Statistics reports that the official unemployment rate for Black people was 10.4% and 4.7% for White people in February 2015. Select all correct answers for this question. O The samples of white and black people are independent. The explanatory variable is the unemployment rate. The response variable is the unemployment rate. The response variable is race.

A researcher is interested in exploring the relationship between calcium intake and weight loss. Two different groups, each with 2626 dieters, are chosen for the study. Group A is required to follow a specific diet and exercise regimen, and also take a 500-mg supplement of calcium each day. Group B is required to follow the same diet and exercise regimen, but with no supplemental calcium. After six months on the program, the members of Group A had lost a mean of 10.4 pounds with a standard deviation of 2.6 pounds. The members of Group B had lost a mean of 11.7pounds with a standard deviation of 2.8 pounds during the same time period. Assume that the population variances are not the same. Construct a 99% confidence interval to estimate the true difference between the mean amounts of weight lost by dieters who supplement with calcium and those who do not. Let Population 1 be the amount of weight lost by Group A, who took a 500-mg supplement of calcium each day, and let Population 2 be…

A researcher is studying the effects of the college experience on attitudes, values, and behaviors and is comparing random samples of freshman and seniors at the same university. Is there a significant difference in political ideology? (On this scale, 10 means "very conservative" and 1 means "very liberal") FRESHMAN SENIORSmean=5.23 mean=5.12s=1.78 s=1.07N=145 N=105

1. To determine whether using a cell phone while driving increases the risk of an accident, a researcher examines accident reports to obtain data about the number of accidents in which a driver was talking on a cell phone. A. Is this a randomized experiment or an observational study? B. Assume that the accident reports show that people were more likely to have an accident while talking on a cell phone. Could this result be due to confounding?

When an audit must be conducted that involves a tedious examination of a large inventory, the audit may be very costly and time consuming if each item in the inventory must be examined. In such situations, the auditor frequently obtains a random sample of items from the complete inventory and uses the results of an audit of the sampled items to check the validity of the company's financial statement. A large company’s financial statement claims an inventory that averages $600 per item. The following data are the auditor’s assessment of a random sample of 75 items from the company’s inventory. The values resulting from the audit are rounded to the nearest dollar. Estimate the mean value of an item in the inventory using a 95% confidence interval. Is there substantial evidence (a 5 .01) that the mean value of an item in the inventory is less than $600? What is the target population for the above inferences? Would normal distribution–based procedures be appropriate for answering the…

Periodically, customers of a financial services company are asked to evaluate the company's financial consultants and services. Higher ratings on the client satisfaction survey indicate better service, with 7 the maximum service rating. Independent samples of service ratings for two financial consultants are summarized here. Consultant A has 10 years of experience, whereas consultant B has 1 year of experience. Use  ? = 0.05  and test to see whether the consultant with more experience has the higher population mean service rating. Assume the population variances are unequal. Consultant A Consultant B n1 = 16 n2 = 10 x1 = 6.85 x2 = 6.25 s1 = 0.69 s2 = 0.75 (a) State the null and alternative hypotheses. -H0:?1 − ?2 = 0 Ha:?1 − ?2 = 0 -H0:?1 − ?2 > 0 Ha:?1 − ?2 = 0  -H0:?1 − ?2 ≠ 0 Ha:?1 − ?2 = 0 -H0:?1 − ?2 = 0 Ha:?1 − ?2 > 0 -H0:?1 − ?2 = 0 Ha:?1 − ?2 ≠ 0 (b) Compute the value of the test statistic. (Round your answer to three decimal places.)…