Patterns in DAta Flashcards
Foty's first lecture
1
Q
Variance Formula
A
Sum(A-Mean)^2/ (n-1)
“Average Square Distance over degree of freedom”
2
Q
Standard Deviation Formula
A
Sqrt ( sum(A-Mean)^2/(n-1)
“Square root of variance”
3
Q
Standard Error
A
SD/ sqRt(n)
4
Q
How does sample size affect variability?
A
It doesn’t
5
Q
How does sample size affect standard error?
A
- Bigger n, means smaller standard Error
- Smaller n, means bigger standard Error
6
Q
What is the rule to figure out 1st, 2nd, and 3rd standard deviations?
A
68–95–99.7 rule
7
Q
What do the four components on a boxplot refer to?
A
- Whisker is the largest/smallst value that isn’t an outlier
- Top box is the 75th percentile
- Median is line in box
- bottom box is the 25th percentile
8
Q
Confidence Interval Formula
A
Ci= X +/- Zcrit * SE
