The Intelligence Quotient IQ test scores for adults are normally distributed

# The intelligence quotient iq test scores for adults

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Question 6. Question : The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find that the mean of this sample is between 98 and 103? Student Answer: 0.3264 0.9428 0.4702 0.7471 Instructor Explanation: We use the formula: ; and . Then, using the "areas under the normal curve" table, P(−0.94 ≤z≤ 1.41) = .3264 + .4207 = .7471. Points Received: 0 of 1 Comments: Question 7. Question : The tread life of tires mounted on light-duty trucks follows the normal probability distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles. Suppose you bought a set of four tires, what is the likelihood the mean tire life of these four tires is between 57,000 and 63,000 miles?
Points Received: 1 of 1 Comments: Question 8. Question : The tread life of tires mounted on light-duty trucks follows the normal probability distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles. Suppose we select a sample of 40 tires and use a simulator to determine the tread life. What is the standard error of the mean? . Points Received: 1 of 1 Comments: Question 9. Question : As the size of the sample increases, what happens to the shape of the distribution of sample means?
Points Received: 1 of 1 Comments: Question 10. Question : A marketing firm is studying consumer preferences for winter fashions in four different months. From a population of women 18-21 years of age, a random sample of 100 women was selected in January. Another random sample of 100 women was selected in March. Another random sample of 100 women was selected in June. Another random sample of 100 women was selected in September. What is the sample size? Student Answer: 100 400 1 Instructor Explanation: There are four samples of 100 each, so the sample size is 100. 4 Points Received: 1 of 1 Comments:
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