Before changes to its management staff, an automobile assembly line operation had a scheduled
A. State the null hypothesis H0 and the alternative hypothesis H1
B. Find the value of the test statistic. (Round to three or more decimal places.)
C. Find the critical value. (Round to three or more decimal places.)
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- One year Chris had the lowest ERA (earned-run average, mean number of runs yielded per nine innings pitched) of any male pitcher at his school, with an ERA of 3.18. Also, Sally had the lowest ERA of any female pitcher at the school with an ERA of 2.52. For the males, the mean ERA was 4.849 and the standard deviation was 0.616. For the females, the mean ERA was 4.766 and the standard deviation was 0.689. Find their respective z-scores. Which player had the better year relative to their peers, Chris or Sally? (Note: In general, the lower the ERA, the better the pitcher.) Chris had an ERA with a z-score of Sally had an ERA with a z-score of (Round to two decimal places as needed.)arrow_forwardA university dean wishes to estimate the average number of hours that freshmen study each week. The standard deviation from previous study is 6 hours. How large a sample must be selected if the dean wants his estimate to be within 0.3 from the true mean with 90% confidence?arrow_forwardAccording to a recent report the battery life for a new line of laptop computers has a mean of 9 hours with a standard deviation of 2.4 hours. If battery life is normally distributed what percentage of new laptops will last between 8 and 11 hours on a single charge?arrow_forward
- It takes an average of 9.1 minutes for blood to begin clotting after an injury. An EMT wants to see if the average will decline if the patient is immediately told the truth about the injury. The EMT randomly selected 49 injured patients to immediately tell the truth about the injury and noticed that they averaged 8 minutes for their blood to begin clotting after their injury. Their standard deviation was 3.31 minutes. What can be concluded at the the a = 0.05 level of significance? a. For this study, we should use Select an answer b. The null and alternative hypotheses would be: Hint: Ho: ? H₁: ? Select an answer Select an answer C c. The test statistic? is -2.326. Enter it here d. The p-value is 0.0121364015. Enter it here e. The p-value is ? a f. Based on this, we should Select an answer the null hypothesis. g. Thus, the final conclusion is that ... (please show your answer to 3 decimal places.) (Please show your answer to 4 decimal places.) The data suggest the populaton mean is…arrow_forwardIt takes an average of 10.2 minutes for blood to begin clotting after an injury. An EMT wants to see if the average will decline if the patient is immediately told the truth about the injury. The EMT randomly selected 60 injured patients to immediately tell the truth about the injury and noticed that they averaged 10.1 minutes for their blood to begin clotting after their injury. Their standard deviation was 1.62 minutes. What can be concluded at the the a = 0.01 level of significance? a. For this study, we should use Select an answer b. The null and altemative hypotheses would be: Họ: Select an answer H1: ? Select an answer c. The test statistic (please show your answer to 3 decimal places.) d. The p-value = e. The p-value is (? va f. Based on this, we should Select an answer v the null hypothesis. g. Thus, the final conclusion is that .. (Please show your answer to 4 decimal places.) O The data suggest the population mean is not significantly less than 10.2 at a = 0.01, so there is…arrow_forwardIt seems these days that college graduates who are employed full time work more than 40 hour weeks. Data are available that can help us decide if this is true. A survey was recently sent to a group of adults selected at random. There were 22 respondents who were college graduates employed full time. The mean number of hours worked per week by these 22 respondents was 43 hours, with a standard deviation of 8 hours. Assume that the population of hours worked per week by college graduates employed full time is normally distributed with mean. Can we conclude that mean is greater than 40 hours? Use the 0.1 level of significance. Perform a one tailed test, and complete the parts below.arrow_forward
- A random sample of 100 observations from a quantitative population produced a sample mean of 28.0 and a sample standard deviation of 6.5. Use the p-value approach to determine whether the population mean is different from 31.arrow_forwardIn Professor Krugman’s economics course, the correlation between the students’ total scores prior to the final examination and their final‑examination scores is ?=0.5.r=0.5. The pre‑exam totals for all students in the course have mean 280280 and standard deviation 40.40. The final‑exam scores have mean 7575 and standard deviation 8.8. Professor Krugman has lost Julie’s final exam but knows that her total before the exam was 300.300. He decides to predict her final‑exam score from her pre‑exam total. (a) Which of the choices is the least‑squares regression line of final‑exam scores on pre‑exam total scores in this course?arrow_forwardSuppose that a report by a leading medical organization claims that the healthy human heart beats an average of 72 times per minute. Advances in science have led some researchers to question if the healthy human heart beats an entirely different amount of time, on average, per minute. They obtain pulse rate data from a sample of 85 healthy adults and find the average number of heart beats per minute to be 76, with a standard deviation of 13. Before conducting a statistical test of significance, this outcome needs to be converted to a standard score, or a test statistic. What would that test statistic be? (Use decimal notation. Give your answer to one decimal place.) test statistic:arrow_forward
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