1. UNIVERSITY OF REGINA
DEPARTMENT OF MATHEMATICS AND STATISTICS
Stat100-002 Elementary Statistics for Applications
Formula sheet for Midterm Test 1
1
Mean: x = n ∑ xi
∑(xi −x)2
Standard deviation: sx = n−1
2
2 (∑ x )
∑ xi − ni
= n−1
2
∑ xi −nx2
= n−1
1 xi −x yi −y
Correlation coefficient: r = n−1 ∑ sx sy
n(∑ xi yi )−(∑ xi )(∑ yi )
=
[n(∑ xi2 )−(∑ xi )2 ][n(∑ y2 )−(∑ yi )2 ]
i
Regression line: ˆ
y = a + bx
sy
Slope: b = r sx
n(∑ xi yi )−(∑ xi )(∑ yi )
= 2
n(∑ xi )−(∑ xi )2
y-intercept: a = y − bx
2
(∑ yi )(∑ xi )−(∑ xi )(∑ xi yi )
= 2
n(∑ xi )−(∑ xi )2