A survey claims that 9 out of 10 doctors recommend aspirin for their patients with headaches. To test this claim against the alternative that the actual proportion of doctors who recommend aspirin is less than 0.90, a random sample of 100 doctors was selected. Suppose you reject the null hypothesis. What conclusion can you reach?
A) There is sufficient evidence that the proportion of doctors who recommend aspirin is less than 0.90.
B) There is sufficient evidence that the proportion of doctors who recommend aspirin is not less than 0.90.
C) There is not sufficient evidence that the proportion of doctors who recommend aspirin is less than 0.90.
D) There is not sufficient evidence that the proportion of doctors who recommend aspirin is not less than 0.90.
Q. 2A survey claims that 9 out of 10 doctors recommend aspirin for their patients with headaches. To test this claim against the alternative that the actual proportion of doctors who recommend aspirin is less than 0.90, a random sample of 100 doctors was selected. Suppose that the test statistic is -2.20. Can you conclude that H0 should be rejected at the (a) = 0.10, (b) = 0.05, and (c) = 0.01 level of Type I error?
A) (a) yes; (b) yes; (c) no B) (a) yes; (b) yes; (c) yes
C) (a) no; (b) no; (c) no D) (a) no; (b) no; (c) yes
Q. 3A survey claims that 9 out of 10 doctors recommend aspirin for their patients with headaches. To test this claim against the alternative that the actual proportion of doctors who recommend aspirin is less than 0.90, a random sample of 100 doctors results in 83 who indicate that they recommend aspirin. The value of the test statistic in this problem is approximately equal to
A) -1.86. B) -4.12. C) -0.07. D) -2.33.
Q. 4A manager of the credit department for an oil company would like to determine whether the mean monthly balance of credit card holders is equal to 75. An auditor selects a random sample of 100 accounts and finds that the mean owed is 83.40 with a sample standard deviation of 23.65. If you wanted to test whether the mean balance is different from 75 and decided to reject the null hypothesis, what conclusion could you reach?
A) There is evidence that the mean balance is not 75.
B) There is no evidence that the mean balance is 75.
C) There is no evidence that the mean balance is not 75.
D) There is evidence that the mean balance is 75.
Q. 5A manager of the credit department for an oil company would like to determine whether the mean monthly balance of credit card holders is equal to 75. An auditor selects a random sample of 100 accounts and finds that the mean owed is 83.40 with a sample standard deviation of 23.65. If you were to conduct a test to determine whether the auditor should conclude that there is evidence that the mean balance is different from 75, which test would you use?
A) Z test of a population mean B) t test of population mean
C) Z test of a population proportion D) t test of a population proportion
Q. 6An entrepreneur is considering the purchase of a coin-operated laundry. The current owner claims that over the past 5 years, the mean daily revenue was 675 with a population standard deviation of 75. A sample of 30 days reveals a daily mean revenue of 625. If you were to test the null hypothesis that the daily mean revenue was 675 and decide not to reject the null hypothesis, what can you conclude?
A) There is enough evidence to conclude that the daily mean revenue was not 675.
B) There is not enough evidence to conclude that the daily mean revenue was not 675.
C) There is not enough evidence to conclude that the daily mean revenue was 675.
D) There is enough evidence to conclude that the daily mean revenue was 675.
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