MATH 221 Week 7 Quiz: Statistics for Decision-Making (Summer 2020) Question And Answers(V2)_Verified Answers.

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MATH-221 Week 7 Quiz: Statistics for Decision-Making ( 2020-v2) Question: (CO 4) From a random sample of 68 businesses, it is found that the mean time that employees spend on personal issues each wee... k is 4.9 hours with a standard deviation of 0.35 hours. What is the 95% confidence interval for the amount of time spent on personal issues? Question: (CO 4) If a confidence interval is given from 8.50 to 10.25 and the mean is known to … 9.375, what is the margin of error? Question: (CO 4) If the population standard deviation of a sample increases without other changes, what is most likely to happen to the confidence interval? Question: (CO 4) From a random sample of 41 teens, it is found that on average they spend 31.8 hours each week online with a population standard deviation of 5.91 hours. What is the 90% confidence interval for the amount of time they spend online each week? Question: (CO 4) A company making refrigerators strives for the internal temperature to have a mean of 37.5 degrees with a population standard deviation of 0.6 degrees, based on samples of 100. A sample of 100 refrigerators have an average temperature of 37.70 degrees. Are the refrigerators within the 90% confidence interval? Question: (CO 4) What is the 97% confidence interval for a sample of 104 soda cans that have a mean amount of 15.10 ounces and a population standard deviation of 0.08 ounces? Question: (CO 4) Determine the minimum sample size required when you want to … 98% confident that the sample mean is within two units of the population mean. … a population standard deviation of 5.75 in a … population. Question: (CO 4) Determine the minimum sample size required when you want to … 80% confident that the sample mean is within 1.5 units of the population mean. … a population standard deviation of 9.24 in a … population. Question: (CO 4) Determine the minimum sample size required when you want to … 75% confident that the sample mean is within twenty units of the population mean. … a population standard deviation of 327.8 in a … population. Question: (CO 4) In a sample of 8 high school students, they spent an average of 25.8 hours each week doing sports with a sample standard deviation of 3.2 hours. Find the 95% confidence interval, assuming the times are …. Question: (CO 4) In a sample of 15 stuffed animals, you find that they weigh an average of 8.56 ounces with a sample standard deviation of 0.08 ounces. Find the 92% confidence interval, assuming the times are …. Question: (CO 4) Market research indicates that a new product has the potential to make the company an additional $3.8 million, with a standard deviation of $1.6 million. If this estimate was based on a sample of 10 customers from a … data set, what would … the 90% confidence interval? Question: (CO 4) Supplier claims that they are 95% confident that their products will … in the interval of 20.45 to 21.05. You take samples and find that the 95% confidence interval of what they are sending is 20.48 to 21.02. What conclusion can … made? Question: (CO 4) In a sample of 18 small candles, the weight is found to … 3.72 ounces with a standard deviation of 0.963 ounces. What would … the 87% confidence interval for the size of the candles, assuming the data are …? Question: (CO 4) In a situation where the population standard deviation was decreased from 5.8 to 3.1, what would … the impact on the confidence interval? Question: (CO 5) A company claims that its heaters last more than 5 years. Write the null and alternative hypotheses and note which is the claim. Question: (CO 5) An executive claim that her employees spend no less than 2.5 hours each week in meetings. Write the null and alternative hypotheses and note which is the claim. Question: (CO 5) In hypothesis testing, a key element in the structure of the hypotheses is that the alternative hypothesis has the ________________________. Question: (CO 5) A landscaping company claims that at least 90% of workers arrive on time. If a hypothesis test is performed that rejects the null hypothesis, how would this decision … interpreted? Question: (CO 5) A textbook company claims that their book is so engaging that more than 55% of students read it. If a hypothesis test is performed that fails to reject the null hypothesis, how would this decision … interpreted? Question: (CO 5) An advocacy group claims that the mean braking distance of a certain type of tire is 75 feet when the car is going 40 miles per hour. In a test of 45 of these tires, the braking distance has a mean of 77 and a population standard deviation of 5.9 feet. Find the standardized test statistic and the corresponding p-value. Question: (CO 5) The heights of 82 roller coasters have a mean of 280.7 feet and a population standard deviation of 59.3 feet. Find the standardized tests statistics and the corresponding p-value when the claim is that roller coasters are less than 290 feet tall. Question: (CO 5) A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is at least 720 hours. A random sample of 51 light bulbs as a mean of 701.6 hours with a population standard deviation of 62 hours. At an α=0.05, can you support the company’s claim using the test statistic? Question: (CO 5) A restaurant claims the customers receive their food in less than 16 minutes. A random sample of 39 customers finds a mean wait time for food to … 15.8 minutes with a population standard deviation of 0.7 minutes. At α = 0.04, can you support the organizations’ claim using the test statistic? Question: (CO 5) A manufacturer claims that their calculators are 6.800 inches long. A random sample of 39 of their calculators finds they have a mean of 6.812 inches with a population standard deviation of 0.05 inches. At α=0.08, can you support the manufacturer’s claim using the p value? Question: (CO 5) A travel analyst claims that the mean room rates at a three-star hotel in Chicago is greater than $152. In a random sample of 36 three-star hotel rooms in Chicago, the mean room rate is $165 with a population standard deviation of $41. At α=0.10, can you support the analyst’s claim using the p-value? Question: (CO 5) A car company claims that the mean gas mileage for its luxury sedan is at least 24 miles per gallon. A random sample of 7 cars has a mean gas mileage of 23 miles per gallon and a standard deviation of 2.4 miles per gallon. At α=0.05, can you support the company’s claim assuming the population is …? Question: (CO 5) A state Department of Transportation claims that the mean wait time for various services at its different location is more than 6 minutes. A random sample of 16 services at different locations has a mean wait time of 9.5 minutes and a standard deviation of 7.3 minutes. At α=0.05, can the department’s claim … supported assuming the population is …? Question: (CO 5) A … car dealer says that the mean price of a three-year-old sport utility vehicle in good condition is $18,000. A random sample of 20 such vehicles has a mean price of $18,450 and a standard deviation of $1930. At α=0.08, can the dealer’s claim … supported assuming the population is …? Question: (CO 5) A researcher wants to determine if daily talks together strengthen a marriage. One group of wives and one group of husbands are selected and have daily talks. After 2 weeks, all are asked if they felt their marriage was stronger based on the talks and the results of the two groups are compared. To … a valid matched pair test, what should the researcher consider in creating the two groups? [Show More]

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