question on psychology stats

PSYCH 2015 STATISTICS PRACTICE
QUESTIONS



QUESTIONS
1. What is crude range?
2. What is extended range?
3. What does the coefficient of variance allow us to do?
4. A sample statistics is denoted by…
5. What values does probability range from?
6. How is probability calculated
7. What does it mean if events are independent?
8. What does mutually exclusive mean?
9. What three characteristics does a graph need to be normally
distributed?
10. What does the area under a curve represent
11. A null hypothesis means
12. What is a z-score
13. What is a z-test used for
14. When do you know of the alternative hypothesis is directional
15. What is a type 1 error
16. What is a type 2 error
17. When is a independent samples t-test used
18. In the example below, where is homogeneity of variance
violated
Sample 1 variance: 4; sample 1 variance: 4;
Sample 1 variance: 12; sample 1 variance: 6;
Sample 1 variance: 16; sample 1 variance: 24;
Sample 1 variance: 20; sample 1 variance: 4;
19. Given an example of an independent sample
20. How is the standard error calculated
21. What is the standard error
22. When would you use a t-test instead of a z-test
23. What is a residual
24. The regression line shows the…
25. What does the standard error of estimate measure
26. Which two terms are used to describe the two variables in the
regression analysis
27. What does Sxy stand for
28. A researcher calculated Pearson’s r and obtained a score of
0.3 which she then calculated Spearman’s r for the same data, but

, obtained a score of 0.45. in this example, why is Spearman’s
correlation higher than the Pearson’s score?
29. The product moment correlation coefficient is also know as
30. Why would you use the Spearman’s coefficient instead of
Pearson’s coefficient
31. Which option is not a Pearson’s coefficient correlation and why
- 1.00
- 0.024
- -0.75
- 1.50
32. A student presents a paper at a conference. Her paper
investigates the factors surrounding poverty. One of her findings is
that poverty and drug abuse are positively correlated, and her
conclusion is that poverty causes drug abuse. What error has she
made?


ANSWERS
1. The difference between the highest and lowest value in the dataset
2. Crude range + 1
3. It allows us to compare the variability of scores in different
distributions
4. s
5. 0 and 1
6. The number of successes divided by the total number of equal
possible outcomes
7. They have no effect/influence on one another
8. It means that they cannot happen at the same time
9. Unimodal, symmetrical and bell shaped
10. Probability
11. There is no significance or difference
12. It is the number of standard deviations that a value lies above
or below the mean
13. To compare a sample mean with the population mean
14. When it indicates the direction it is going in – increasing or
decreasing
15. When the null hypothesis is rejected when its true
16. When the null hypothesis is accepted when its false
17. It is used when there is a significant difference between the
means of two independent samples
18. Sample 1 variance: 20; sample 1 variance: 4;
19. Any example where the 2 or more groups have no
relationship with each other
20. By dividing the sample standard deviation by the square root
of the sample size
21. When the population standard deviation is unknown