MATH 221 MATH WEEK 7 QUIZ 60 POINTS | 30 Questions and Answers solutions | Download To Score An A.

WEEK 7: QUIZ Due Oct 21 at 11:59pm Points 60 Questions 30 Available Oct 14 at 12am - Oct 22 at 11:59pm 9 days Time Limit 120 Minutes Instructions . Correct! (5.72, 5.8 8) (5.73, 5.87) Correct! (CO6) If the standard deviation of a sample decreases without other changes, what is most likely to happen to the confidence interval? widens You Answered cannot determine does not change Correct Answer narrows See text page 301 Correct! (CO6) A company making refrigerators strives for the internal temperature to have a mean of 37.5 degrees with a standard deviation of 0.6 degrees, based on samples of 100. A sample of 100 refrigerators have an average temperature of 37.53 degrees. Are the refrigerators within the 90% confidence interval? No, the temperature is outside the confidence interval of (37.40, 37.60) Correct! Yes, the temperature is within the confidence interval of (37.40, 37.60) No, the temperature is outside the confidence interval of (36.90, 38.10) Yes, the temperature is within the confidence interval of (36.90, 38.10) Correct! (CO6) Determine the minimum sample size required when you want to be 98% confident that the sample mean is within two units of the population mean. Assume a standard deviation of 4.82 in a normally distributed population. 31 Correct! 32 33 34 Correct! (CO6) Determine the minimum sample size required when you want to be 75% confident that the sample mean is within fifteen units of the population mean. Assume a standard deviation of 327.8 in a normally distributed population You Answered Correct Answer 632 785 See text page 304 Correct! Correct! Correct! (CO6) Supplier claims that they are 95% confident that their products will be 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 be made? You Answered The supplier is less accurate than they have claimed The supplier products have a higher mean than claimed The supplier products have a lower mean than claimed Correct Answer The supplier is more accurate than they claimed See text pages 298-300 Correct! (CO6) In a situation where the standard deviation was increased from 3.1 to 5.8, what would be the impact on the confidence interval? It would become narrower due to the increased standard deviation It would remain the same as standard deviation does not impact confidence intervals It would become narrower with more values Correct! It would become wider due to the increased standard deviation Question 16 2 / 2 pts (CO7) A company claims that its heaters last at most 5 years. Write the null and alternative hypotheses and note which is the claim. Correct! Ho: μ ≤ 5 (claim), Ha: μ 5 Ho: μ ≤ 5, Ha: μ 5 (claim) Ho: μ 5 (claim), Ha: μ ≤ 5 Ho: μ = 5 (claim), Ha: μ ≥ 5 Question 17 2 / 2 pts (CO7) An executive claims that her employees spend more than 2.5 hours each week in meetings. Write the null and alternative hypotheses and note which is the claim. Ho: μ 2.5, Ha: μ ≤ 2.5 (claim) Ho: μ = 2.5 (claim), Ha: μ ≥ 2.5 Correct! Ho: μ ≤ 2.5, Ha: μ 2.5 (claim) Ho: μ ≤ 2.5 (claim), Ha: μ 2.5 Question 18 0 / 2 pts (CO7) In hypothesis testing, a key element in the structure of the hypotheses is that the claim is . Correct Answer either one of the hypotheses both hypothesis You Answered the null hypothesis the alternative hypothesis See text page 349 (CO7) A landscaping company claims that at least 90% of workers arrive on time. If a hypothesis test is performed that fails to reject the null hypothesis, how would this decision be interpreted? You Answered There is not sufficient evidence to support the claim that more than 90% of workers arrive on time There is sufficient evidence to support the claim that more than 90% of workers arrive on time Correct Answer There is sufficient evidence to support the claim that a least 90% of workers arrive on time There is not sufficient evidence to support the claim that at least 90% of workers arrive on time See text page 356 Correct Answe You Answered You Answered Correct Answe (CO7) The heights of 82 roller coasters have a mean of 281.4 feet and a standard deviation of 59.3 feet. Find the standardized tests statistics and the corresponding p-value when the claim is that roller coasters are more than 290 feet tall. Correct Answer z-test statistic = -1.31, p-value = 0.0945 z-test statistic = 1.31, p-value = 0.1891 You Answered z-test statistic = 1.31, p-value = 0.0945 z-test statistic = -1.31, p-value = 0.1891 See text page 365 (CO7) 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 705.4 hours with a standard deviation of 62 hours. At an α=0.05, can you support the company’s claim using the test statistic? Claim is the alternative, fail to reject the null and cannot support claim as the test statistic (-1.68) is in the rejection region defined by the critical value (-1.96) Claim is the alternative, reject the null and support claim as test statistic (-1.68) is not in the rejection region defined by the critical value (-1.96) Correct Answer Claim is the null, reject the null and support claim as test statistic (-1.68) is in the rejection region defined by the critical value (-1.645) You Answered Claim is the null, fail to reject the null and cannot support claim as test statistic (-1.68) is not in the rejection region defined by the critical value (-1.645) See text pages 368-370 Question 24 0 / 2 pts (CO7) 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 be 15.8 minutes with a standard deviation of 0.7 minutes. At α = 0.04, can you support the organizations’ claim using the test statistic? Correct Answer Claim is the alternative, reject the null so support the claim as test statistic (-1.78) is in the rejection region defined by the critical value (-1.75) Claim is the alternative, fail to reject the null so cannot support the claim as test statistic (-1.78) is not in the rejection region defined by the critical value (-2.05) You Answered Claim is the null, reject the null so cannot support the claim as test statistic (-1.78) is in the rejection region defined by the critical value (-2.05) Claim is the null, fail to reject the null so support the claim as test statistic (-1.78) is not in the rejection region defined by the critical value (-1.75) See text pages 368-370 Correct Answe You Answered (CO7) 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 standard deviation of $41. At α=0.10, what type of test is this and can you support the analyst’s claim using the p-value? You Answered Claim is the null, reject the null as p-value (0.029) is less than alpha (0.10), and cannot support the claim Claim is the alternative, fail to reject the null as p-value (0.029) is less than alpha (0.10), and can support the claim Claim is the null, fail to reject the null as p-value (0.029) is less than alpha (0.10), and cannot support the claim Correct Answer Claim is the alternative, reject the null as p-value (0.029) is less than alpha (0.10), and can support the claim See text pages 365-366 Question 27 0 / 2 pts (CO7) 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 1.1 miles per gallon. At α=0.05, can you support the company’s claim? No, since the test statistic is not in the rejection region defined by the critical value, the null is not rejected. The claim is the null, so is supported Correct Answer No, since the test statistic is in the rejection region defined by the critical value, the null is rejected. The claim is the null, so is not supported Yes, since the test statistic is not in the rejection region defined by the critical value, the null is not rejected. The claim is the null, so is supported You Answered Yes, since the test statistic is not in the rejection region defined by the critical value, the null is rejected. The claim is the null, so is not supported See text pages 379-380 (CO7) A state Department of Transportation claims that the mean wait time for various services at its different location is less 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 7.6 minutes. At α=0.05, can the department’s claim be supported? Yes, since p of 0.043 is less than 0.07, reject the null. Claim is alternative, so is supported Correct Answer No, since p of 0.043 is greater than 0.05, fail to reject the null. Claim is alternative, so is not supported You Answered Yes, since p of 0.043 is greater than 0.05, fail to reject the null. Claim is null, so is supported No, since p of 0.043 is greater than 0.05, reject the null. Claim is null, so is not supported See text page 382 Question 29 2 / 2 pts (CO7) A used 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 $1140. At α=0.08, can the dealer’s claim be supported? Yes, since the test statistic of 1.77 is in the rejection region defined by the critical value of 1.46, the null is rejected. The claim is the null, so is supported Correct! Yes, since the test statistic of 1.77 is not in the rejection region defined by the critical value of 1.85, the null is not rejected. The claim is the null, so is supported No, since the test statistic of 1.77 is in the rejection region defined by the critical value of 1.85, the null is rejected. The claim is the null, so is not supported No, since the test statistic of 1.77 is close to the critical value of 1.85, the null is not rejected. The claim is the null, so is supported Correct Answe You Answered Quiz Score: 30 out of 60 Show Less