A researcher finds a .40 correlation between the number of years a student has access to a computer and his or her attitude toward mathematics. The study used 20 subjects. A correlation that is not statistically significant leads to the conclusion that:
a. the correlation in the population is actually 0.
b. there is not enough evidence of a correlation between variables.
c. computer use and math attitude are not related.
d. all of these are true.
Ques. 2A researcher finds a .40 correlation between the number of years a student has access to a computer and his or her attitude toward mathematics. The study used 20 subjects. The correlation is statistically significant at what level?
a. .05 c. .001
b. .01 d. None of these are true.
Ques. 3A researcher finds a .40 correlation between the number of years a student has access to a computer and his or her attitude toward mathematics. The study used 20 subjects. What are the degrees of freedom in this case?
a. 39 c. 19
b. 38 d. 18
Ques. 4A researcher wants a 90 percent chance of rejecting the null hypothesis at the one-tailed .05 level with an effect size of .15 . The sample size needed is about
a. 140.
b. 160.
c. 180.
d. 200.
e. 380
Ques. 5The greatest statistical power occurs when
a. the sample is small and heterogeneity is small.
b. the sample is small and heterogeneity is large.
c. the sample is large and heterogeneity is small.
d. the sample is large and heterogeneity is large.
Ques. 6An administrator will implement a new science curriculum if there is good evidence that it is more effective than the present curriculum. Otherwise he will continue with the present curriculum. The administrator should use a
a. directional test. c. difference test.
b. non-directional test. d. non-difference test.
Ques. 7Which one of the following statements is true?
a. Type I errors are inherently more serious than Type II errors.
b. Type II errors are inherently more serious than Type I errors.
c. The relative seriousness of a Type I or a Type II error is a judgment.
d. Typically in behavioral sciences, Type II errors are regarded as more serious.
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