According to a study conducted by the California Division of Labor Research and Statistics, roofing is one of the most hazardous occupations. Of 3,514 worker injuries that caused absences for a full workday or shift after the injury, 26% were attributable to falls from high elevations on level surfaces and 14% to burns or scalds. Assume that 3,514 injuries can be regarded as a random sample from the population of all roofing injuries in California. Construct a 95% confidence interval for the proportion of all injuries that are due to falls.
Question 1 options:
Upper Bound: 0.3545, Lower Bound: 0.1855
Upper Bound: 0.4325, Lower Bound: 0.1255
Upper Bound: 0.2745, Lower Bound: 0.2455
Upper Bound: 0.2325, Lower Bound: 0.2955
Question 2 (4 points)
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A consumer group claims that wireless companies are worsening their customer service, with the time customers are kept on hold when contacting the company reaching an average of 4.4 minutes. You collect data on 40 random customer service calls and find that the sample mean time a customer is kept on hold is 3.5 minutes and standard deviation is 48 seconds (0.8 minutes). Develop a 90% confidence interval for the mean time customers are kept on hold.
Question 2 options:
Upper Bound: 3.76, Lower Bound:3.24
Upper Bound: 4.85, Lower Bound:4.02
Upper Bound: 3.98, Lower Bound:3.02
Upper Bound: 4.02, Lower Bound:2.88
Question 3 (2 points)
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Suppose the mean weight of King Penguins found in an Antarctic colony last year was 15.4 kg. In a sample of 35 penguins same time this year in the same colony, the mean penguin weight is 14.6 kg. Assume the population standard deviation is 2.5 kg. Select the most appropriate null and alternative hypothesis that will help deciding whether the penguin weight does not differ from last year?
Question 3 options:
H0=15.4, Ha≠15.4
H0=14.6, Ha≠14.6
H015.4
H014.6
Question 4 (2 points)
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Your faculty adviser claims that the average GMAT score required to be accepted into top university MBA programs is at most 663. To test this, you decided to research 27 MBA programs across the United States and found the average GMAT score for accepted applicants to be 634 with a standard deviation of 65. Select the most appropriate null and alternative hypothesis that will support your adviser’s claim?
Question 4 options:
H0 ≥ 634, Ha<634
H0=663, Ha≠663
H0 ≤ 663, Ha>663
H0 ≥ 663, Ha<663
Question 5 (2 points)
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The United States government claims DUI arrests average 21,000 per state per year. A sample of size n=10 states finds the mean to be 42,000. If DUI arrests are normally distributed with a standard deviation of 28,584. Select the most appropriate null and alternative hypothesis that will help deciding whether DUI arrests are differ than government claims.
Question 5 options:
H0 = 21000, Ha ≠ 21000
H0 = 42000, Ha ≠ 42000
H0 42000
H0 = 28584, Ha ≠ 28584
Question 6 (4 points)
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According to Thomson Financial, last year the majority of companies reporting profits had beaten estimates. A sample of 188 companies showed that 115 beat estimates, 38 matched estimates, and 35 fell short. Determine the margin of error with 99% confidence interval for the proportion that matched estimates.
Question 6 options:
0.1214
0.0754
0.0247
0.1515
Question 7 (4 points)
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Your faculty adviser claims that the average GMAT score required to be accepted into top university MBA programs is at least 663. To test this, you decided to research 27 MBA programs across the United States and found the average GMAT score for accepted applicants to be 634 with a standard deviation of 96. Develop null and alternative hypothesis that will support your adviser’s claim at the 1% significance level and calculate the p value?
Question 7 options:
0.0643
0.0008
0.1255
0.5146
Question 8 (4 points)
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Suppose the mean weight of King Penguins found in an Antarctic colony last year was 15.4 kg. In a sample of 35 penguins same time this year in the same colony, the mean penguin weight is 14.6 kg. Assume the population standard deviation is 2.5 kg. Develop null and alternative hypothesis that will help deciding whether the penguin weight does not differ from last year at the 1% significance level and calculate the p value?
Question 8 options:
0.0669
0.0008
0.1255
0.3546
Question 9 (4 points)
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The United States government claims DUI arrests average 22,096 per state per year. A sample of size n=20 states finds the mean to be 44,002. If DUI arrests are normally distributed with a standard deviation of 28,584. Develop null and alternative hypothesis that will help deciding whether DUI arrests are higher than government claims at the 1% significance level and calculate the p value?
Question 9 options:
0.0014
0.0008
0.2345
0.3546
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