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Regarding the probability of Type I error (α) and Type II error (β) , which statement is true?


A) β > α
B) β < α
C) α + β = 1
D) Power = 1 - β.

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The Melodic Kortholt Company will change its current health plan if at least half the employees are dissatisfied with it. A trial sample of 25 employees shows that 16 are dissatisfied. The p-value for a right-tailed test is:


A) .1337
B) .4192
C) .0901
D) .0808

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We can assume that the sample proportion is normally distributed if:


A) we have 10 successes in the sample.
B) we have 10 failures in the sample.
C) we have both 10 successes and 10 failures in the sample.
D) the population is known.

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The researcher's null hypotheses is H0: σ2 = 420. A sample of n = 18 items yields a sample variance of s2 = 512. The test statistic is:


A) 34.09
B) 20.72
C) 14.77
D) must know α to answer.

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A hypothesis test may be statistically significant, yet have little practical importance.

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True

In a two-tailed test, a statistician got a z test statistic of 1.47. What is the p-value?


A) .0708
B) .1416
C) .0874
D) .0301

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A power curve for a mean is at its lowest point when the true μ is very near μ0.

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If sample size increases from 25 to 100 and the level of significance stays the same, then:


A) the risk of Type II error would decrease.
B) the risk of Type I error would decrease.
C) the risk of both Type I and Type II errors would decrease.
D) the risk of neither Type I nor Type II error would decrease.

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Given that in a one-tailed test you cannot reject H0, can you reject H0 in a two-tailed test at the same α?


A) Yes.
B) No.
C) Maybe.

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B

If the null and alternative hypotheses are H0: μ ≤ 100 and H1: μ > 100, the test is right-tailed.

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For a right-tailed test of a hypothesis for a population mean with n = 14, the value of the test statistic was t = 1.863. The p-value is:


A) between .05 and .025.
B) between .10 and .05.
C) greater than .10.
D) less than .01.

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In graphing power curves, there is a different power curve for each sample size n.

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In the hypothesis H0: π = π0, the value of π0 is derived from the sample.

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Increasing the level of significance shifts the power curve upward, ceteris paribus.

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For a right-tailed test of hypothesis for a population mean with known σ, the test statistic was z = 1.79. The p-value is:


A) .0367
B) .9633
C) .1186
D) .0179

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Power is the probability of rejecting the null hypothesis when it is false and is equal to 1 - β.

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True

Which of the following is correct?


A) When sample size increases, both α and β may decrease.
B) Type II error can only occur when you reject H0.
C) Type I error can only occur if you fail to reject H0.
D) The level of significance is the probability of Type II error.

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"Currently, only 20 percent of arrested drug pushers are convicted," cried candidate Courageous Calvin in a campaign speech. "Elect me and you'll see a big increase in convictions." A year after his election a random sample of 144 case files of arrested drug pushers showed 36 convictions. For a right-tailed test, the p-value is approximately:


A) 0.9332
B) 0.0668
C) 0.0435
D) 0.0250

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In hypothesis testing, we are trying to prove the null hypothesis.

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The critical value of a hypothesis test is based on the researcher's selected level of significance.

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