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practice_hw.docPrintable Practice Quiz # 4.4
Please answer each question to the best of your ability.
1. Do professional journals try to publish Type II Errors? Yes or No?
2. Support for the null hypothesis means that you have correctly (accepted or rejected?) the null hypothesis.
3. In a p=.10 two-tailed test what % of the curve falls on in the reject the null hypothesis region?
4. A one-tailed test, with p=.05, what % of the curve falls in the accept the null hypothesis region?
5. The Type I Error means you have (accepted or rejected?) the alternative hypothesis. .
6. If the alpha (or p value) level is set at .20, what is the likelihood of a
significant result occurring, due to mere chance?
7. If the alpha level is set at 10%, what is the likelihood of a
significant result occurring, due to mere chance?
8. If the beta (accept the null region) is set at .95 what is the likelihood of a
significant result occurring, due to mere chance?
9. If the beta level is set at 80% what is the likelihood of a
significant result occurring, due to mere chance?
10. What statistical test is used if you have one sample, and N > 30?
11. What type of statistical t-test is used if have the sample s.d., N, the sample mean of ONE sample, and the population average?
12. What does it mean if you have a Type I Error?
_
13. Xi - X)2 tells you to do four things to the values of X.
What are those four things, in proper order?
14. The average or mean in a left skewed distribution would be ______ (left, right, or the same as) the median for that sample? (hint, see page 79)
Printable Practice Quiz # 4.4
z’s, t’s &correlated t-sub-d’s
Well, we’ve covered enough basics, time to start doing some real statistics. After you’ve finished practicing, take the Graded Problems for Week 4 in the Quiz section. Examples for the problems can be found on pages 146, 158, 180, 191.
Problem 1
If: x
X= 8.00
15. Which statistical test would determine if the single score (X) was significantly lower than ?
16. What is the probability of getting this value for X? (Hint page 279)
17. If alpha were set at .05, is this difference statistically significant?
Problem 2
If: s
Mean of X = 13.00
N = 22
18. Which t-test would tell if the Mean of X was significantly higher than
19. Alpha is set at .05 for this One-Tailed test, what are the degrees of freedom?
20. What is the standard error for this calculation?.
21. Is this difference between the mean of X and statistically significant?
Problem 3
If: Subject Post-Test Score Pre-Test Score Difference
(Post – Pre = D)
1 8 2 6
22. Which statistical t-test would tell if the post-test scores were
significantly larger than the pre-test scores?
23. Alpha is set at .05 for this One-Tailed test, what are the degrees of freedom?
24. What is the tabled value for this test? (Hint see page 415).
25. What is the average increase or difference in scores? (Hint average of D)
26. What is the standard deviation of the difference in scores (Hint sD)
27. What is the calculated t and is this difference statistically significant?
28. For the X=20, 25, 22, 25, 38, 39 and using only your calculator what is X=
29. Using the X values above X2= Mean of X = s.d. X =
T of the D
30. What are three advantages of using a Correlated Samples t-test.
(Hint: you’ll have to google this one….).
1st Advantage:
2nd Advantage:
3rd Advantage:
Problem 4
If: Pre Scores Post Scores Difference
28 27
31. Which class of statistical test would tell if the Post scores were
significantly lower than the Pre Scores? One tailed or two?
32. Alpha is set at .05 for this One-Tailed test, what are the degrees of freedom?
33. What is the tabled value for this test? (Hint see page 415).
34. What is the average for Pre Scores? Average for Post Scores?
35. What is the calculated t and is this difference statistically significant?
Problem 5 (see page 201 for EXCEL directions, and page 207 for the TI-84 directions)
If: Group A (Exp) Group B (Cntl)
28 37
36. Which t-test should be used on this type of data?
37. Alpha is set at .05 for this test, what are the degrees of freedom?
38. What is the tabled value for this test? (Hint see page 415).
39. What is the average for Group A? Average for Group B?
40. What is the calculated t (see page 315, module 11 directions for Excel)
is this difference statistically significant?
After you’ve finished practicing, take the Graded Problems for Week 4 in the Quiz section.
