Variance Formula
Sum(A-Mean)^2/ (n-1)
“Average Square Distance over degree of freedom”
Standard Deviation Formula
Sqrt ( sum(A-Mean)^2/(n-1)
“Square root of variance”
Standard Error
SD/ sqRt(n)
How does sample size affect variability?
It doesn’t
How does sample size affect standard error?
- Smaller n, means bigger standard Error
What is the rule to figure out 1st, 2nd, and 3rd standard deviations?
68–95–99.7 rule
What do the four components on a boxplot refer to?
Confidence Interval Formula
Ci= X +/- Zcrit * SE