  Quiz Over Chapter 3 of the 6th Edition

Bivariate Correlation

The Key Concept Behind Correlation: Relationship
1. The concept of "relationship" cannot be investigated if we measure each person in a group one time only on a single variable.
2.  True False
3. What kind of relationship exists among the math and science quiz scores shown below:
4.  High-high, low-low High-low, low-high Little systematic tendency one way or the other

 Person Math Science Will 7 5 Jill 9 3 Bill 8 4

5. If 10 points are added to each person's math score in the previous question, what kind of relationship will exist between the revised math and science quiz scores?
6.  High-high, low-low High-low, low-high Little systematic tendency one way or the other
Scatter Diagrams
1. If a scatter diagram is used to show how 20 people score on 2 variables, the scatter diagram will have __ axes and __ dots.
2.  2, 20 2, 40 20, 2 40, 2
3. If a "high-low, low-high" relationship exists between two variables, the "path" of dots in the scatter showing this relationship will extend from:
4.  upper-right to lower-left upper-left to lower right
5. Where would you be located in a scatter diagram if you've got the top scores and its a "high-high, low-low" relationship?
6.  Top left Top right Bottom left Bottom right
The Correlation Coefficient
1. Which of the following correlations is "highest"?
2.  -.35 +.80 -.05 +.65 -.95
3. Since a correlation of +1 is "perfect," a correlation of -1 is as "imperfect" as can be.
4.  True False
5. "Positive" is to "negative" as "direct" is to "_______."
7. What lower-case letter is generally used to represent a correlation coefficient?
8.  c n p r z
9. When used in reference to correlation coefficients, the adjectives "modest" and "moderate" mean the same thing.
10.  True False
11. If r is +1.00, the means of the 2 variables will necessarily be identical to each other.
12.  True False
The Correlation Matrix
1. Which two variables had the 2nd highest correlation in Excerpt 3.6?
2.  Agreeableness and Extraversion Agreeableness and Openness Openness and Conscientiousness Neuroticism and Extraversion Agreeableness and Conscientiousness
3. If all possible bivariate ("pairwise") correlations are computed among 10 variables, there will be at least ___ (how many) correlation coefficients in the correlation matrix.
4.  9 18 45 81 100
5. If a correlation matrix has 4 rows & 4 columns, then how many variables were there to start with?
6.  4 5 Either 4 or 5
Different Kinds of Correlational Procedures
1. What kind of measurement scale leads to rank-ordered data?
2.  nominal ordinal interval ratio
3. Which term--dichotomous or nominal--covers the other (and covers other things too)?
4.  Dichotomous Nominal
5. If people are called "tall" if they're over 5'6" (and "short" if they're not), is this a true dichotomy?
6.  Yes No
7. What 2 symbols are used to designate Spearman's correlation?
8.  r and s ordinal r and r interval rs and s rs and r
9. Which correlational procedure handles data sets having ties better than does Spearman's?
10.  Kendall's tau tetrachoric phi
11. What do the letters "pb" stand for in the notation rpb?
12.  Pearson bivariate Pearson biserial point bivariate point biserial
13. If we were to correlate hand preference (left vs. right) with gender (male vs. female), which correlational procedure would be most appropriate:  phi or tetrachoric?
14.  Phi Tetrachoric
15. What letter of the alphabet is used to denote Cramer's correlational procedure?
16.  C H R V
1. If the correlation is greater than .90, can we assume that a causal relationship exists?
2.  Yes No
3. In Excerpt 3.7, the coefficient of determination for Self-efficacy and Action planning (from the fruit consumption study) is equal to __ .
4.  .03 .16 .40 .60 It's impossible to say
5. If the correlation between height and weight is 0.70, what percentage of the variability among the height scores is associated with variability among the weight scores?
6.  7% 30% 49% 70%
7. Depending on their location, outliers can either increase or decrease the size of r.
8.  True False
9. Does the term "linear" apply to these 8 pairs of math (M) and geography (G) scores?
10.  Yes No
 Name M G Joe 2 1 Sam 1 2 Sue 3 2 Ann 2 3 Bob 4 3 Dan 3 4 Eve 5 4 Pam 4 5

11. Two variables are considered to be "independent" if the correlation of scores on the variables turns out to be close to __ .
12.  -1.00 0.00 +1.00
13. The decision as to how an r should be labeled (e.g., as "high" or "moderate" or "low") is quite subjective, and different researchers might use different labels even though their correlation coefficients are exactly the same size.
14.  True False
A Few Extra Questions that are Supposed to be More Challenging
1. The coefficient of determination never will turn out to be a negative number, even if there's a negative correlation between the 2 variables being correlated.
2.  True False
3. If a correlation is equal to 0.50, this indicates that the mean on 1 of the 2 variables is half as large as the mean on the other variable.
4.  True False
5. Given 8 totally different scores, it is possible to create a "high-high, low-low" situation by (a) positioning the top 4 scores in the X column & (b) positioning the lowest 4 scores in the Y column.
6.  True False