Exam 18: Samples and Blocks

An army depot that overhauls ground mobile radar systems is interested in improving its processes.One problem involves troubleshooting a particular component that has a high failure rate after it has been repaired and reinstalled in the system.The shop floor supervisor believes that having standard work procedures in place will reduce the time required for troubleshooting this component.Time (in minutes) required troubleshooting this component without and with the standard work procedure is recorded for a sample of 19 employees. assuming that we define our differences as Time without standard work procedure - Time with standard work procedure, the correct alternative hypothesis is

Using the sample paired data below, construct a 90% confidence interval for the population mean of all differences x-y x 5.0 4.7 4.4 5.1 6.4 y 4.7 3.5 4.0 5.8 4.1

A mid-sized company has decided to implement an enterprise resource planning (ERP) system, and management suspects that many of its employees are concerned about the planned implementation.Managers are considering holding informational workshops to help decrease anxiety levels among employees.They randomly select 16 employees to participate in a pilot workshop.These employees were given a questionnaire to measure anxiety levels about ERP before and after participating in the workshop.At the 90% confidence level, what is the margin of error for the mean difference in anxiety levels pre- and post-workshop? Pre-workshop anxiety level 7 6 9 5 6 7 5 7 6 4 3 2 1 3 4 2 Post-workshop anxiety level 4 3 7 3 4 5 4 6 5 3 2 2 1 3 4 3 Difference (Post - Pre) -3 -3 -2 -2 -2 -2 -1 -1 -1 -1 -1 0 0 0 0 1

An army depot that overhauls ground mobile radar systems is interested in improving its processes.One problem involves troubleshooting a particular component that has a high failure rate after it has been repaired and reinstalled in the system.The shop floor supervisor believes that having standard work procedures in place will reduce the time required fortroubleshooting this component.Time (in minutes) required troubleshooting this component Without and with the standard work procedure is recorded for a sample of 19 employees.In order to determine if having a standard work procedure in place reduces troubleshooting time, they should use

A mid-sized company has decided to implement an enterprise resource planning (ERP) system, and management suspects that many of its employees are concerned about the planned implementation.Managers are considering holding informational workshops to help decrease anxiety levels among employees.To determine whether such an approach would be effective, they randomly select 16 employees to participate in a pilot workshop.These employees were given a questionnaire to measure anxiety levels about ERP before and after participating in the workshop.To determine if anxiety levels about ERP decreases as a result of the workshop, they should use a

An army depot that overhauls ground mobile radar systems is interested in improving its processes.One problem involves troubleshooting a particular component that has a high failure rate after it has been repaired and reinstalled in the system.The shop floor supervisor believes that having standard work procedures in place will reduce the time required for troubleshooting this component.Time (in minutes) required troubleshooting this component without and with the standard work procedure is recorded for a sample of 19 employees.Thestandard error of the mean difference is Without Standard Work Procedure With Standard Work Procedure Difference Without - With 142 119 23 144 118 26 153 126 27 148 119 29 146 121 25 149 125 24 138 116 22 145 120 25 153 124 29 160 138 22 163 135 28 170 144 26 169 142 27 151 128 23 152 131 21 167 141 26 164 140 24 165 140 25 163 138 25

Previous surveys reported that more men than women trade stocks onlinE.A local brokerage firm randomly selected a sample of investors.They found that 45 out of 234 men traded online and 42 out of 251 women traded onlinE.The 95% confidence interval for the difference in proportions is

An agricultural company wanted to know if a new insecticide would increase corn yields. Eight test plots showed an average increase of 3.125 bushels per acrE.The standard deviation of the increases was 2.911 bushels per acre .Determine a 90% confidence interval for the mean increase in yield.

Which of the following is not an assumption and/or condition for the paired t-test?

Before being released to market, a drug company tests a new allergy medication for potential side effects.A random sample of 160 individuals with allergies was selected for the study. The new allergy medication was randomly assigned to 80 of them, and another popular allergy medication already on the market (Brand C ) was assigned to the rest.Out of the 80 given the new allergy medication, 14 reported drowsiness; 22 of the 80 taking Brand C reported drowsiness.The 95% confidence interval for the difference in proportions reporting drowsiness is -0.028 to 0.228.Which of the following is correct?

Ten different families were tested for the average number of gallons of water they used per day before and after viewing a conservation video.A 90% confidence interval for the difference of the means after and before the training, $\mu _ { A } - \mu _ { B }$ was determined to be (-10.8, -4.2).

A high school coach uses a new technique in training middle distance runners.He records the times for 4 different athletes to run 800 meters before and after this training.A 95% confidence interval for the difference of the means before and after the training, $\mu _ { B } - \mu _ { A }$ was determined to be (2.6, 4.3).

A mid-sized company has decided to implement an enterprise resource planning (ERP) system, and management suspects that many of its employees are concerned about the planned implementation.Managers are considering holding informational workshops to help decrease anxiety levels among employees.They randomly select 16 employees to participate in a pilot workshop.These employees were given a questionnaire to measure anxiety levels about ERP before and after participating in the workshop. If we let d = post-workshop anxiety level - pre-workshop anxiety level, the correct alternative hypothesis to determine if this approach was successful is

Ten different families are tested for the number of gallons of water a day they use before and after viewing a conservation video.Construct a 90% confidence interval for the mean of the differences. Before 33 33 38 33 35 35 40 40 40 31 After 34 28 25 28 35 33 31 28 35 33