interpreting SD Flashcards
1
Q
what percentage of values lie within +1 SD of x
A
68%
2
Q
what percentage of values lie within +2 SD of x
A
95%
3
Q
what percentage of values lie within +3 SD of x
A
99.7%
4
Q
what does it mean if observations are clustered around the mean
A
samller the sigma, smaller the SD
5
Q
what does a tall distribution mean
A
observations closer to the mean
6
Q
coefficient of variance
equation
A
SD/ mean
7
Q
what does a high CoV mean
A
most variation
8
Q
pearsons coeffieicnt of skewness (PCS)
equation
A
3 (mean- median)/ SD
9
Q
what is the PCS if the distribution is symmetrical
A
> -0.5 and < 0.5
10
Q
what is the PCS if the distribution is negativley skewed
A
> -1 and < -0.5
11
Q
what is the PCS if the distribution is positivley skewed
A
> 0.5 and < 1
