Part : Multiple-Choice Questions (5 points) Please write your answer choice on t

Question

Part : Multiple-Choice Questions (5 points) Please write your answer choice on the line for each of the multiple-choice questions 1. The null hypothesis a. states that the treatment has no effect b. is denoted by the symbol H c. is always stated in terms of sample statistics d. All of the other choices are correct 2, A researcher expects a treatment to produce an increase in the population mean. Assuming a normal distribution, what is the critical z-score for a one-tailed test with ,01? a. +2.33 b. ±2.58 c. +1.65 d. ±2.33 3. By selecting a smaller alpha level, a researcher is . a. attempting to make it easier to reject Ho b. better able to detect a treatment effect c. reducing the risk of a Type I error d. All of the options are consequences of selecting smaller alpha level. · In what circumstances is the t statistic used instead of a z-score for a hypothesis test? a. The t statistic is used when the sample size is n-30 or larger. b. The t statistic is used when the population mean is unknown. c. The t statistic is used when the population variance (or standard deviation) is unknown. d. The t statistic is used if you are not sure that the population distribution is normal. 5. One assumption for the t test is that a. the population distribution is normal b. the sample size be less than 30 C, the value of is known d. the t distribution is normal

Explanation / Answer

1) (a) States that the treatment has no effect

2) (a) +2.33 (as it is a right tailed test)

3) (c) Reducing the risk of a Type I error

(Reducing alpha makes it more difficult to reject H0 and hence detect treatment effect. For eg. if P value is 0.03 and alpha is 0.05, then we reject H0, as p value is < alpha, but if we bring down alpha to 0.01, then we fail to reject H0, with the same P value as P value is now > alpha.)

4) (c) The t statistic is used when the population variance (or standard deviation) is unknown.

5) (a) The population distribution is normal.

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