Statistics Formulas Flashcards
1
Q
Mean (ungrouped)
A
Sum of x / n
2
Q
Mean (grouped)
A
Sum of freq multiply x / n
3
Q
Variance (grouped)
A
(Sum of freq multiply x^2 / n ) - mean^2
4
Q
Standard Deviation
A
Square root variation
Square root Sxx
5
Q
Variance (ungrouped)
A
(Sum of x ^2/n) - mean^2
6
Q
Sxx
A
Sum of x^2 - ((sum of x)^2 / n )
7
Q
Frequency Density
A
Fd = f/cw
8
Q
Variant for possion approximation
A
Np(1-p)
9
Q
Good ness of fit
A
(Sum of Oi^2 / Ei ) -N
10
Q
Ei for each cell of contingency table
A
(Row total x column total) / grand total
11
Q
Degrees of freedom
A
V = (row-1)(column-1)
12
Q
Histogram (mean)
A
(Sum of (freq x midpoint) )/ total freq
13
Q
Chi squared tests, finding p for binomial
A
(Sum of f x X) / ( no trials x N )
14
Q
Chi squared tests, finding mean for poison
A
(Sum of f x X) / N
15
Q
Test Statistic
A
Definition of X
