Statistic Quizzes

Question 1

· 
  The primary contributor to the standard error of the difference between the means is the standard error of the means of the two populations.


Answer

True

False


Question 2

· 
  Assume a research report says t(43) = 2.37, α <0.02. For this study, confidence is <0.02.


Answer

True

False

Question 3

· 
  If a single set of subjects serves in both treatment groups, the study should be analyzed with an independent subjects t test.


Answer

True

False

Question 4

· 
  The region of rejection is in the tails of the distribution.


Answer

True

False


Question 5

· 
  If tabled t is 2.23 and calculated t is 2.24, the calculated t can be considered statistically significant.


Answer

True

False


Question 6

· 
  In a two-sample t test, α =0.05 and t(74) = +2.15. How many subjects are in this study?


Answer

· 72.

· 73.

· 74.

· 76.

· There is not enough information to tell.

Question 7

· 
  What is the purpose of a two-sample t test?


Answer

	· a.	To determine whether two means are more different than expected by chance.
	· b.	To compare the actual mean difference between groups with the difference desired by the researcher.
· c.	To equate groups on one or more extraneous variables.
· d.	To be twice as confident of your results as you would be in a one-sample t test.

Question 8

· 
  In a two-sample t test, if the observed difference between the sample means turns out to be one that would rarely occur when the null hypothesis is true, what should we do?


Answer

	a.	· Reject the null hypothesis.
	b.	· Retain the null hypothesis.
	c.	· Repeat the test until we get a more probable difference between the sample means.
	d.	· Change the level of significance (type 1 error).




10 points  

Question 9

· 
  Suppose that a researcher decides that he must obtain a type 1 error level of no more than 0.01 to reject the null hypothesis. After analyzing his data he finds that the results are significant at p = 0.05 but not at p = 0.01. If he is not able to change the maximum allowed type 1 error level, then the researcher should


Answer

	· a.	· Retain the null hypothesis because 0.05 is greater than 0.01.
·	· b.	· Retain the null hypothesis because 0.05 is merely sampling error.
·	· c.	· Reject the null hypothesis because 0.05 is close to 0.01.
·	· d.	· Reject the null hypothesis because 0.05 is greater than 0.01.




Question 10

· 
  What is the purpose of the change in formula from an independent sample t test to a related sample t test?


Answer

·	· a.	To simplify the calculation process when samples are dependent.
·	· b.	· To remove the unwanted correlation introduced by the dependence of subjects between the IV conditions.
·	· c.	· To remove the influence of unwanted or outlier cases in each sample.
·	· d.	To weight the contribution of each sample by the number of cases present in that sample.