ductory Statistics Third Edition Perdisco Assessment Below is a set of assessable homework questions on this topic, selected by your professor. Take care! Do not submit your answers until you have read all the instructions and answered the questions carefully. When you submit your answers, you will receive immediate feedback. Navigating this page: Submit answers: Submit your answers for immediate grading Bookmark: Save this question set so that you can come back to it later 1 of 3 ID: MST.FET.E.CIMSK.01.0030A [2 marks] marks] Menso is an organisation for people with high Intelligence Quotients (IQs). Menso is investigating the average IQ of primary school students to determine whether its entry requirements should be altered for younger people. A sample of 40 primary school students have been randomly selected from schools throughout the country. The sample mean IQ of those students was calculated as 107. It is known that the population standard deviation of the IQs of all people is 10. It is assumed that this standard deviation will also apply specifically to the IQs of the primary school students. Calculate the upper and lower bounds of the 99% confidence interval for the mean IQ of primary school students. You may find this standard normal table useful. Give your answers to 2 decimal places. a) Upper bound = b) Lower bound = 2 of 3 ID: MST.FET.E.CIMSK.02.0010A [3 marks] marks] As a stock analyst, your boss, Jerry, has asked you to compile some information on stock of Southern Infrastructure Corporation including a 95% confidence interval for the mean daily return that he needs to include in a report to senior management. He says that he is also not sure exactly what a 95% confidence interval means and would like you to add an explanation. You have been following the share price of Southern Infrastructure Corporation and have recorded the daily return (as a percentage) for the last 120 days. The data is presented here: Download the data Daily returns (%) 1.291 0.608 0.116 0.983 0.015 1.556 0.427 0.861 0.923 1.12 0.514 0.784 -0.498 1.895 0.321 0.953 1.809 0.435 0.361 0.304 1.184 0.572 1.111 0.598 0.672 0.277 1.399 0.464 0.56 1.207 0.569 1.175 0.188 0.851 0.834 1.484 0.329 1.804 0.51 0.731 0.13 0.665 1.397 1.105 0.696 0.139 0.511 1.839 -0.412 0.131 0.276 0.008 1.28 0.032 1.097 -0.473 0.571 0.151 0.205 1.179 -0.197 0.242 0.592 1.12 0.995 1.54 0.07 0.568 -0.098 0.782 0.657 1.034 0.416 -1.045 0.31 1.472 0.406 0.18 0.06 1.575 1.842 -0.096 2.509 0.289 1.695 0.565 0.186 0.645 1.176 1.311 -0.793 0.743 0.316 0.086 0.707 -0.12 0.814 0.666 -0.041 0.142 0.117 -0.182 0.839 0.523 1.384 0.35 0.363 0.414 0.487 -0.147 0.245 1.101 2.683 -0.523 0.343 0.566 1.137 1.101 0.729 0.257 Historically, the standard deviation in daily return for this stock is 0.7%. Complete the report to your boss. Give your numeric answers to 3 decimal places. Sent: May 4, 2016 11:10 AM To: Jerry Kendall Subject: Southern Infrastructure Corp. stock info Dear Jerry, Here are the results gathered from the collected data: Assuming a population standard deviation in daily return of 0.7%, the 95% confidence interval for the mean daily return is: a) b) This means that approximately 95% of sample means will be within the interval given above using a process that gives correct results in 95% of cases, the population mean daily return is within the interval given above the population mean daily return is definitely within the interval given above on approximately 95% of days in a given period the stock makes a return within the interval given above 3 of 3 ID: MST.FET.E.CIMSK.03.0030A [1 mark] mark] WMB is a car manufacturer. The company is trying to estimate the cost of building a particular car part. Specifically, the company would like to construct a 90% confidence interval for the mean cost of building this part. For the purposes of constructing the interval, the company is assuming that the population standard deviation in this cost is $20.53. You were dozing in the meeting and so you didn't hear the proposed value for the margin of error for the confidence interval. However you did hear that, in order to achieve this proposed margin of error, a sample size of 219 items is required. You also remember hearing the boss say that the company couldn't afford to collect a sample this large. To reduce the sample size, a quick decision was made to double the size of the margin of error. All other parameters of the situation are to remain the same. Based on this information, calculate the required sample size to construct a confidence interval with this wider margin of error. Round your answer up to the nearest whole number. Required sample size = Perdisco / latin /, v., to learn thoroughly 2010 Perdisco Terms Of Use | Privacy Policy | Wednesday, May 04, 2016, 21:03 http://www.perdisco.com.au Introductory Statistics Third Edition Perdisco Assessment Below is a set of assessable homework questions on this topic, selected by your professor. Take care! Do not submit your answers until you have read all the instructions and answered the questions carefully. When you submit your answers, you will receive immediate feedback. Navigating this page: Submit answers: Submit your answers for immediate grading Bookmark: Save this question set so that you can come back to it later 1 of 3 ID: MST.FET.E.CIMSU.01.0020A [4 marks] marks] The Police Department is investigating the need for a speed camera to be implemented on Hasty Road. A sample of 60 cars passing through that road on a particular day were randomly selected and their speeds recorded. The speed limit on Hasty Road is 60 miles per hour (mph). The mean speed for the sample was calculated as 43 mph. The standard deviation of the speeds for the sample was calculated as 4 mph. The standard deviation for the population of cars driving on Hasty Road is unknown. a) Select all the techniques that are commonly used to construct a confidence interval for the mean when the population standard deviation () is unknown: Approximate the population standard deviation () with the sample standard deviation (s) Replace the sample size (n) with n-1 Approximate the standard normal distribution with the Student's t distribution Decrease the confidence level to compensate for the increased margin of error b) Calculate the upper and lower bounds of the 95% confidence interval for the mean speed traveled on Hasty Road. You may find this Student's t distribution table useful. Give your answers in mph to 2 decimal places. Upper bound = mph Lower bound = mph 2 of 3 ID: MST.FET.E.CIMSU.02.0030A [1 mark] mark] A medical team is studying the the ramifications of obesity in society. As part of this study, a control group of 36 people has been collected, and the resting heart rates (in beats per minute) has been measured in these subjects. The average heart rate in this control group is 60.6. The sample standard deviation for this group is 3.3. Calculate the 95% confidence interval for the mean heart rate in the population. You may find this Student's t distribution table useful. Give your answers to 2 decimal places. 3 of 3 ID: MST.FET.E.CIMSU.03.0020A [1 mark] mark] Tyler and Jack are both studying a numerical variable X. Both students want to estimate the population mean of this variable, and they each intend to collect a sample, calculate a sample mean and construct a 95% confidence interval. Each student will collect their own sample, but both samples will have 30 items in them. When constructing his confidence interval, Tyler assumes a value for the population standard deviation, . In contrast, Jack does not assume a value for the population standard deviation. Jack calculates the sample standard deviation, s, and uses this in his confidence interval. As it turns out, the sample standard deviation that Jack calculates turns out to be slightly less than the value assumed by Tyler for the population standard deviation. Based on this information, it is true to say that: both confidence intervals will be of the same width it is impossible to tell which confidence interval will be wider Jack's confidence interval will be wider than Tyler's Tyler's confidence interval will be wider than Jack's Perdisco / latin /, v., to learn thoroughly 2010 Perdisco Terms Of Use | Privacy Policy | Wednesday, May 04, 2016, 21:03 http://www.perdisco.com.au Introductory Statistics Third Edition Perdisco Assessment Below is a set of assessable homework questions on this topic, selected by your professor. Take care! Do not submit your answers until you have read all the instructions and answered the questions carefully. When you submit your answers, you will receive immediate feedback. Navigating this page: Submit answers: Submit your answers for immediate grading Bookmark: Save this question set so that you can come back to it later 1 of 3 ID: MST.FET.E.CIP.01.0010A [2 marks] marks] A friend tells you that she has conducted a survey to find the proportion of people in her university that utilize the campus internet cafe at least once a day. She has collected a sample and calculated a sample proportion of p = 0.60. She uses this value to calculate a confidence interval for the population proportion. Your friend says that she is not going to tell you the sample size or the level of confidence used in her construction, and wants you to guess what the confidence interval is. She gives you 5 options. Select the interval(s) that, based on the information given, could possibly be the confidence interval your friend calculated: the interval between 0.50 and 0.70 the interval between 0.60 and 0.80 the interval between 0.50 and 0.80 the interval between 0.40 and 0.70 the interval between 0.40 and 0.60 2 of 3 ID: MST.FET.E.CIP.02.0020A [2 marks] marks] A survey was run by a high school student in order to determine what proportion of mortgage-holders in his town expect to own their house within 10 years. He surveyed 155 mortgage holders and found that the proportion of these that did expect to own their house within 10 years is 0.68. The student decides to construct a 95% confidence interval for the population proportion. You may find this standard normal table useful for the following questions. a) Calculate the margin of error that the high school student will have. Give your answer as a decimal to 3 decimal places. Margin of error = A different high school student sees this survey and decides to try and repeat it. This second high school student also surveys 155 mortgage holders, but this student finds that the proportion of these that do expect to own their house within 10 years is 0.84. This student also constructs a 95% confidence interval for the population proportion. b) Calculate the margin of error that the second student will have. Give your answer as a decimal to 3 decimal places. Margin of error = 3 of 3 ID: MST.FET.E.CIP.03.0020A [3 In a survey of 117 small business owners, a total of 89 marks] marks] of the owners had decided to downsize in the year following the Global Financial Crisis (GFC). a) Calculate the proportion of surveyed small business owners that downsized. Give your answer as a decimal to 2 decimal places. Sample proportion = A 95% confidence interval is to be constructed for the proportion of all small business owners that decide to downsize after the GFC. You may find this standard normal table useful for the following questions. If you use your answer to part a) in the following calculations, use the rounded version. b) Calculate the lower bound for the confidence interval. Give your answer as a decimal to 3 decimal places. Lower bound for confidence interval = c) Calculate the upper bound for the confidence interval. Give your answer as a decimal to 3 decimal places. Upper bound for confidence interval = Perdisco / latin /, v., to learn thoroughly 2010 Perdisco Terms Of Use | Privacy Policy | Wednesday, May 04, 2016, 21:04 http://www.perdisco.com.au Introductory Statistics Third Edition Perdisco Assessment Below is a set of assessable homework questions on this topic, selected by your professor. Take care! Do not submit your answers until you have read all the instructions and answered the questions carefully. When you submit your answers, you will receive immediate feedback. Navigating this page: Submit answers: Submit your answers for immediate grading Bookmark: Save this question set so that you can come back to it later 1 of 2 ID: MST.FET.IS.SD.01.0010A [2 marks] marks] When selecting a sample, there are several methods of selection available. a) From the list below, select the sample selection method that generally guarantees that every sample of a given size stands an equal chance of being selected: systematic sampling stratified sampling cluster sampling none of the above A company with hundreds of employees has hired a third party human resources agency. The agency is to study the employees and their level of job satisfaction, and to discover if the company needs to change anything about its management of human resources. As part of this study, the agency wants to survey a selection of employees from within the company. Four members of the agency propose four different sampling plans for the survey. Alvin: 'The marketing department of the company is reflective of the rest of the company in terms of job satisfaction. We should simply survey that department.' Bonnie: 'We have access to the names of every employee in the company. We should survey 50 people from the company by putting every name in a list and choosing 50 names completely at random.' Crystal: 'The company is made up of 60% men and 40% women. I believe that men and women will have different levels of job satisfaction, and we should force our sample to have 60% men and 40% women.' Donald: 'As Bonnie says, we should put every name in a list. However, we should only pick one person at random, from the first ten people on the list, and then pick every tenth person thereafter.' b) The member that is proposing a stratified sample is: Alvin Bonnie Crystal Donald 2 of 2 ID: MST.FET.IS.SD.02.0010A [1 mark] mark] A CEO is trying to decide whether or not to include a day-care center in his company building. He notices that, of the 200 employees at the company, 50 have children while 150 do not. He splits the employees up into these two groups, and randomly selects 10 employees with children and 30 employees without. He surveys these 40 people on their opinion on whether a day-care center in the building would be worth having. This is an example of a: systematic sample cluster sample simple random sample stratified sample Perdisco / latin /, v., to learn thoroughly 2010 Perdisco Terms Of Use | Privacy Policy | Wednesday, May 04, 2016, 21:04 http://www.perdisco.com.au