U7

Question 1

what is a correlation

Answer 1

• not cause and effect
• describes relationship between 2 variables

Question 2

correlations indicate …
and are described by _____ and _____

Answer 2

• degree of consistency and variability between 2 variables

direction and strength

Question 3

regression analysis and what it indicates

Answer 3

• how closely scatterplot fits regression line (line of best fit)
• indicates relative accuracy of a prediction

Question 4

the ______ the relationship between variables is the ____ the accuracy when trying to predict

Answer 4

stronger
better

Question 5

r value of perfect correlation and no correlation

Answer 5

perfect positive = 1.00
perfect negative = -1.00
none = 0.00

Question 6

PPMC (Pearson product-moment correlation)

Answer 6

• r value
• determines strength between 2 variables in a linear relationship
• relies on covariance (how x and y vary together)
• greater r more predictive of relationship

Question 7

low correlation doesn’t eliminate ________ nor does a high correlation prove it

Answer 7

causation

Question 8

little to no relationship
fair relationship
moderate to good relationship
good to excellent relationship

Answer 8

= 0.00 - 0.25
= .25 - .50
= .50 - .75
= .75 +

Question 9

strength of relationships in social sciences

Answer 9

0.00 - 0.10 = weak
0.11 - 0.30 = moderate
0.30 + strong

Question 10

inverse vs direct linear relationships

Answer 10

inverse = decline
direct = incline

Question 11

limitations of PPMC

Answer 11

• 2 groups w no relationship can produce a strong correlationand vice versa
• extreme data points can have large effect
• relationship could be present but not evident from PPMC since not linear relationship

Question 12

coefficient of determination

Answer 12

how much one variable can explain the degree of variation in a pint from the regression line

Question 13

equation of a straight line

Answer 13

Y^ = a +bx

Y^ = predicted y value
x = measured x value
a = y intercept
b = slope regression line

Question 14

residual

Answer 14

(Y-Y^)
measures magnitude of error of prediction

Question 15

the predicted value of a score won’t = raw scores unless r =

Answer 15

1.00

Question 16

SEE

Answer 16

sd of an average
for predicting future data (avg score for x-value +/- value)

Question 17

RCT = randomized control trial

Answer 17

establishes cause and effect (efficiency)
- placebo and test group
- random assignment

Question 18

t or f
examinning correlations between previous data can prove cause and effect relationships

Answer 18

f

Question 19

negative r value = ________ relationship
positive r value = ______ relationship

Answer 19

inverse
direct

Question 20

null hypothesis vs alternative hypothesis

Answer 20

H0: p=0
H1: p not = 0

Question 22

test statistic must be _______ then or equal to critical value to reject H0 (signifying a significant relationship)

Answer 22

greater