A computer manufacturer estimates that its line of minicomputers has, on average, 8.7 days of downtime per year. To test this claim, ananalyst contacts seven companies that own one of these computers and is allowed to access company computer records. It isdetermined that, for the sample, the average number of downtime days is 5.1, with a sample standard deviation of 1.6 days. Assumingthat number of downtime days is normally distributed, test to determine whether these minicomputers actually average 8.7 days ofdowntime in the entire population. Let a = .01.Appendix A Statistical Tables(Round your answer to 2 decimal places, e.g. 15.25.)The value of the test statistic iseTextbook and MediaSolutionSave for Later-3.71 and wereject the null hypothesisAttempts: unlimited Submit Answer

The hypothesized mean is μ0=8.7. The sample size is n=7. The sample mean is x¯=5.1. The sample…

Answered: A computer manufacturer estimates that…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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A computer manufacturer estimates that its line of minicomputers has, on average, 7.3 days of downtime per year. To test this claim, a researcher contacts seven companies that own one of these computers and is allowed to access company computer records. It is determined that, for the sample, the average number of downtime days is 4.3, with a sample standard deviation of 1.3 days. Assuming that number of downtime days is normally distributed, test to determine whether these minicomputers actually average 7.3 days of downtime in the entire population. Let α = .01. Appendix A Statistical Tables (Round your answer to 2 decimal places.) The value of the test statistic is enter the value of the test statistic and we choose between reject and fail to reject the null hypothesis .
A newly hired human resource analyst proposes to senior management that the number of employee sick days could be reduced by converting to a flex-time work schedule. Assume that historical records show that the population mean for employee sick days is 5.28 days with a population standard deviation of 2.14 days. Senior management agrees to a one-year pilot study involving fifty employees working a flex-time schedule. After one-year, the analyst reports to management that the fifty employees in the study averaged 4.68 sick days during the year. Does the flex-time work schedule reduce employee sick days? What are the appropriate null and alternative hypotheses for this study? Assuming that the H0 is true, what is the probability of the analyst arriving at these results? (i.e., what is the p-value?) Does the flex-time work schedule reduce employee sick days? Using a 0.05 level of significance, what is the necessary value of the test statistic to justify rejecting…
1. A random sample of 30 warehouses was selected as part of a study on electricity usage, and the number of kilowatt-hours (kWh) was recorded for each warehouse in the sample for the March quarter of 2019. The average usage was found to be 375kWh. In a very large study in the March quarter of the previous year it was found that the standard deviation of the usage was 81kWh. Assuming the standard deviation is unchanged and that the usage is normally distributed, calculate a 99% confidence interval for the mean usage in the March quarter of 2019.
A national online business magazine reports that the average cost of a speeding ticket in Miami, including court fees, is $220. A local police department claims that this amount has increased. To test their claim, they collect data from a simple random sample of 16 drivers who have been fined for speeding in the last year. Assuming that the distribution of speeding ticket costs is normally distributed and the population standard deviation is $13, is there sufficient evidence to support the police department’s claim at the 0.02 level of significance?
A very large company is interested in its employees' productivity. The company reports from its historical data that its employees spend a mean of 164 minutes per employee (on a typical day) dealing with email. To test this claim, an independent consultant chooses 26 employees at random and finds that those employees spend a sample mean of 172 minutes dealing with email, with a sample standard deviation of 21 minutes. Assume that the population of amounts of time employees spend dealing with email is approximately normally distributed. Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.05 level of significance, to reject the claim that u, the mean number of minutes employees spend dealing with email, is equal to 164. (a) State the null hypothesis H, and the alternative hypothesis H, that you would use for the test. Ho: I H: OSO D=D (b) Perform at test and find the p-value. Here is some information to help you with your t test.
A district councilor informs the prospective developer of a shopping centre that the average monthly income per household in his district is 2500 Great Britain Pound. Suppose that the household income in the district is approximately normally distributed and that the standard deviation is about 200 Great Britain Pound, based on an earlier study. For a random sample of 25 households, the mean household income is found to be 2400 Great Britain Pound. At a 5% level of significance, can we justify the district councilor’s claim? If not, at what significance level we can justify?
A national online business magazine reports that the average cost of a speeding ticket in Miami, including court fees, is $220. A local police department claims that this amount has increased. To test their claim, they collect data from a simple random sample of 16 drivers who have been fined for speeding in the last year. Assuming that the distribution of speeding ticket costs is normally distributed and the population standard deviation is $14, is there sufficient evidence to support the police department's claim at the 0.02 level of significance? Speeding Ticket Costs in Miami $226 $215 $200 $248 $233 $242 $213 $247 $217 $221 $237 $217 $241 $212 $232 $211 Copy Data Step 2 of 3: Compute the value of the test statistic. Round your answer to two decimal places.
Judy is a psychology student who participates in three competitions: Swimming, cycling, and running in one event. In the last competition, Judy completed the swimming race in 13 minutes and 20 seconds (800 seconds), cycling in 33 minutes and 52 seconds (2032 seconds), and the running race in 17 minutes and 3 seconds (1023 seconds. Completion times for participants in Swimming are normally distributed with a mean of / = 725 seconds and a standard deviation o - 50 seconds. Completion times for participants in Cycling* are normally distributed with a mean of = 2182 seconds and a standard deviation o= 75 seconds. And completion times for participants in Running are normally distributed with a mean of u = 1083 seconds and a standard deviation o = 60 seconds. In which competition race (swimming, cycling, or running) was Judy's performance better, relative to others on average who took part in that competition? Justify your answer, quoting. relevant statistics as part of your explanation
A tire manufacturer claims that the best quality tire sold by the company will last an average of 35,000 miles before wearing out. The standard deviation is 5600 miles. To check on the accuracy of this claim, a consumer’s group randomly selects numerous samples each consisting of 100 such tires manufactured by this company. Within what limits should the average mileage of 90% of these samples lie?
A metropolitan transportation authority has set a bus mechanical reliability goal of 3,900 bus miles. Bus mechanical reliability is measured specifically as the number of bus miles between mechanical road calls. Suppose a sample of 100 buses resulted in a sample mean of 3,975 bus miles and a sample standard deviation of 275 bus miles. Complete parts (a) and (b) below.
Suppose the mean wait-time for a telephone reservation agent at a large airline is 40 seconds. A manager with the airline is concerned that business may be lost due to customers having to wait too long for an agent. To address this concern, the manager develops new airline reservation policies that are intended to reduce the amount of time an agont needs to spend with each customer. A random sample of 250 customers results in a sample mean wait-time of 39.1 seconds with a standard deviation of 4.2 seconds. Using a=0.05 level of significance, do you believe the new policies were effective in reducing wait time? Do you think the results have any practical significance? 6-7 (Round to two decimal places as needed.) Calculate the P-value. P.value = Round to three decimal olaces as needed.) ick to select your answer(s).
A national online business magazine reports that the average cost of a speeding ticket in Miami, including court fees, is $220. A local police department claims that this amount has increased. To test their claim, they collect data from a simple random sample of 16 drivers who have been fined for speeding in the last year. Assuming that the distribution of speeding ticket costs is normally distributed and the population standard deviation is $14, is there sufficient evidence to support the police department's claim at the 0.02 level of significance? Copy Data Speeding Ticket Costs in Miami $226 $215 $200 $248 $233 $242 $213 $247 $217 $221 $237 $217 $232 $211 $241 $212 Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Họ : 1 = 220 Hap 220

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