Question 14 5 pts Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy of your results and explanation. A manufacturing company with over 2500 warehouse workers decided to change their warehouse hours from a daily 8 am to 4 pm schedule to a multiple-shift schedule where one group of workers will work mornings (5 am to 1 pm) and another group of workers will work afternoons/evenings (1 pm to 9 pm). In response to worker's complaints about childcare with the new schedule, the manager of the company would like to survey the workers to estimate the proportion of workers who would be interested in a company before/after school childcare center at the warehouse. Two sampling plans for selecting the workers to be surveyed are under consideration by the manager. One plan is to take a simple random sample the warehouse workers and then survey those workers. The other plan is to take a stratified random sample of the warehouse workers and then survey those workers. A) Describe a simple random sampling procedure that the manager could use to select 200 workers from the 2,500 workers at the warehouse. B) If a stratified random sampling procedure is used, give one example of an effective variable on which to stratify in this survey. Explain your reasoning. C) Describe one statistical advantage of using a stratified random sample over a simple random sample in the context of this study Question 15 5 pts Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy of your results and explanation. In search of a flea repellent that is safer than the ones that are currently on the market, scientists have developed a new formula that is less toxic than the current formula on the market, making it safer for dogs and cats. Scientists also believe that the new formula will be more effective than the formulas currently on the market. To test the effectiveness of the new formula versus that of the current most widely used flea repellent, 100 adult dogs and 100 adult cats will be used in the study. 200 enclosed small rooms at a boarding facility with an equal number of fleas in each room will be used in the study. After the formula is applied to the animal, the animal will be put into a room for one hour, and the number of live fleas on the animal will be counted at the end of the hour. A) Suppose this study is to be conducted using a completely randomized design. Describe a randomization process to assign all 200 animals to either the new formula or the current repellent with an equal number in each group. B) Suppose this study is to be conducted using a block design. Describe a randomization process to assign the 200 animals to groups. C) Which of the designs, the one in part A or the one in part B is better for testing the effectiveness of the new formula versus the current repellent on the market? Justify your answer. Question 14 5 pts Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy of your results and explanation. A manufacturing company with over 2500 warehouse workers decided to change their warehouse hours from a daily 8 am to 4 pm schedule to a multiple-shift schedule where one group of workers will work mornings (5 am to 1 pm) and another group of workers will work afternoons/evenings (1 pm to 9 pm). In response to worker's complaints about childcare with the new schedule, the manager of the company would like to survey the workers to estimate the proportion of workers who would be interested in a company before/after school childcare center at the warehouse. Two sampling plans for selecting the workers to be surveyed are under consideration by the manager. One plan is to take a simple random sample the warehouse workers and then survey those workers. The other plan is to take a stratified random sample of the warehouse workers and then survey those workers. A) Describe a simple random sampling procedure that the manager could use to select 200 workers from the 2,500 workers at the warehouse. B) If a stratified random sampling procedure is used, give one example of an effective variable on which to stratify in this survey. Explain your reasoning. C) Describe one statistical advantage of using a stratified random sample over a simple random sample in the context of this study Question 15 5 pts Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy of your results and explanation. In search of a flea repellent that is safer than the ones that are currently on the market, scientists have developed a new formula that is less toxic than the current formula on the market, making it safer for dogs and cats. Scientists also believe that the new formula will be more effective than the formulas currently on the market. To test the effectiveness of the new formula versus that of the current most widely used flea repellent, 100 adult dogs and 100 adult cats will be used in the study. 200 enclosed small rooms at a boarding facility with an equal number of fleas in each room will be used in the study. After the formula is applied to the animal, the animal will be put into a room for one hour, and the number of live fleas on the animal will be counted at the end of the hour. A) Suppose this study is to be conducted using a completely randomized design. Describe a randomization process to assign all 200 animals to either the new formula or the current repellent with an equal number in each group. B) Suppose this study is to be conducted using a block design. Describe a randomization process to assign the 200 animals to groups. C) Which of the designs, the one in part A or the one in part B is better for testing the effectiveness of the new formula versus the current repellent on the market? Justify your
