Basic HTML Version
Q
uantitative
R
easoning &
P
roblem
S
olving
336
© 2014 Pacific Crest
M
athematical Language
Terms and notation
correlation coefficient
— a statistical measure of the strength of the relationship between two sets
of numbers (or variables)
simple linear regression
— the process of building a model of the relationship between two variables
by fitting a linear equation to observed data
z-score
—
a statistical measurement of a score’s relationship to the mean in a group of scores. Az-score
of 0 means the score is the same as the mean. A z-score can also be positive or negative, indicating
whether it is above or below the mean and by how many standard deviations.
The z-score is calculated by subtracting the mean of a data set from the value of an
individual data point and dividing that number by the standard deviation for the data set:
x x
z
σ
−
=
I
nformation
What you need to know
R
eadings
R
esources
M
ethodology
C
alculating
the
L
inear
R
egression
E
quation
Scenario:
Build the Linear Regression Equation to predict the test score for a student who
scores 17 on the quiz.
quiz
test
15
74
16
95
10
75
12
76
9
80
6
75
10
81
18
81
2
36
quiz
test
20
93
6
75
16
70
5
64
3
43
6
66
13
83
16
73
Step
Explanation
1.
Define
x
and
y
Identify the independent variable x and the dependent variable y
WATCH
IT WORK!
Independent variable (
x
): quiz
Dependent variable (
y
): test