Question

multiple choice:

4) The sampling distribution of x̅1-x̅2 has a mean value equal to .

a. 0 b. μ1-μ2 c. N d. Sx̅1- x̅2

True-false questions

5) If we reject H0 one can say the experimental results are significant.

6) By making alpha smaller we can decrease the probability of making a Type I error.

7) As the probability of making a Type I error goes down by making α more stringent, the probability of making a Type II error goes up.

8) Power is the probability of making a correct decision when H0 istrue.

9) If one conducts an experiment and ends up failing to reject H0, it’s probably because the experiment was not powerful enough.

10) Increasing sample size, making α more stringent, and increasing the effect of the independent variable all increase power.

11) In general critical t value is greater than critical z value at the same α level.

12) The 95% confidence interval means that 95% of the time x̅=μ. 1

3) For a sample mean, the 99% confidence interval is wider than the 95% confidence interval.

14) The larger the sample size the more likely x̅ is close to μ.

15) Changing sample size has no effect on power when using the t test.

16) For the independent two-sample t test, increasing sample variances decreases power

Answer 1

Ans:

4)The sampling distribution of x̅1-x̅2 has a mean value equal to 0

5)True

6)True,as type I error=alpha

7)True,smaller the alpha,less likely to reject the null hypothesis,so type II error increases.

8)False,as Power is the probability of making a correct decision when H0 is false.

9)True

10)True

11)True,as t distribution is wider for smaller n

12)False

13)True,larger the confidence level,wider the confidence interval

14)False,as larger the n,larger the test statistic,more likely to reject the null hypothesis.

15)False,larger the n,larger the power

16)True,Larger the variance,larger the standard error,smaller the test statistic,larger the probability of type II error,smaller the power