Two coworkers commute from the same building. They are interested in whether or not there is any variation in the time it takes them to drive to work. They each record their times for 20 commutes. The first worker's times have a variance of 12.2. The second worker's times have a variance of 16.9. The first worker thinks that he is more consistent with his commute times and that his commute time is shorter. Test the claim at the 10% level. What is the p-value?

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.)…

Two chemical companies can supply a raw material. The concentration of a particular element in this material is important. The mean concentration for both suppliers is the same, but you suspect that the variability in concentration may differ for the two companies. The standard deviation of concentration in a random sample of n₁ = 10 batches produced by company 1 is s₁ = 4.7 grams per liter, and for company 2, a random sample of n₂ = 16 batches yield s₂ = 5.8 grams per liter. Is there sufficient evidence to conclude that the two populations variances differ? Use a = 0.05. a. Because 0.321 < 0.657 <3.77, fail to reject the null hypothesis b. Because 0.265 < 0.657 <3.12, fail to reject the null hypothesis c. Because 0.386 < 0.657 <3.01, fail to reject the null hypothesis d. None among the choices

The sample mean and sample variance of Fire Jata valves are X = 104 and 5² = 16. If three of the data values are 102, 100, and 105, What are the other two Jaté Values?

What percentage of Contra Costa County adults supports a ban on assault-style weapons? Suppose that we survey a random sample of 100 adults living in Contra Costa County and find that 62% support a ban on assault-style weapons. According to  a  2015 study by  the Pew  Research Center, 57% of U.S.  adults  favor a ban on assault-style weapons. Assuming that the variability in random samples will be the same in Contra Costa County as in the U.S., find the 95% confidence interval to estimate the proportion of CCC adults that favor a ban on assault-style weapons.   g. Are we confident that the percentage of Contra Costa County residents that supports a ban is greater than the percentage nationwide as reported by the Pew Research Center? Why or why not?

Clara and Rose work at different companies. Clara earns an annual salary of 55,500 and Rose earns an annual salary of 58,000, but they are curious to know whose salary is closer to the mean salary at her company. Clara calculates a z-score of z=−0.45 for her salary, when compared to her company, and Rose calculates a z-score of z=−0.33. Whose salary is closer to the mean salary at her company? Select the correct answer below:

Two companies produce small motorcycles of varying quality. An important measure of quality is the top speed the motorcycle can obtain on a flat surface. Do the following data provide evidence that the average top speed of cycles from these two companies differ? Report the p-value to two decimal places. Do not assume equal variances.    Top Speed in mph from Company 1 Top Speed in mph from Company 2 21.5 53.0 20.3 40.1 49.6 49.3 43.8 51.6 50.5 52.6 52.5 50.6 47.8   37.0   33.2

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 a = 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 = 6,81 X2 = 6.25 %3D S1 = 0.68 S2 = 0.75 (a) State the null and alternative hypotheses. O Hoi H1 - H2 = 0 Hai H1- Hz>0 O Ho: H1 - 42 = 0 Hại H1 - H2# 0 O Ho: H1 - H2 > 0 %3D Ha: H1 - H2 = 0 O Ho: H1 - Hz # 0 Hai Hy - Hz = 0 Hoi H1 - H2 = Hai H1- H2 = 0 (b) Compute the value of the test statistic. (Round your answer to three decimal places.) 19.191 (c) What is the p-value?…

Rebecca and Emma began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Rebecca took a test in English and earned a 71, and Emma took a test in Social Studies and earned a 70.4. Use the fact that all the students' test grades in the English class had a mean of 71.5 and a standard deviation of 10.7, and all the students' test grades in Social Studies had a mean of 64.1 and a standard deviation of 9.5 to answer the following questions. a) Calculate the z-score for Rebecca's test grade. b) Calculate the z-score for Emma's test grade. = Z c) Which person did relatively better? Rebecca O Emma O They did equally well.