Exam 2 - Biostats equations

Equation for median location

equation for deviation score

Equation for standard deviation (for a population or sample)

Equation for standard deviation (for an estimation of population variability (ie using sample for a population)

equation for variance

Equation for Z score

Score (X) - mean (X bar) / Standard deviation (S)

Equation for Effect size

population mean 1 - population mean 2/ standard deviation of a population

Cohens d - meaningless

d < 0.20

Cohens d - small

d = 0.20 - 0.49

Cohens d - medium

d = 0.50 - 0.79

Cohens d - large

d = 0.80+

how to find IQR

1) arrange in order (H → L) in an array

2) find N (total number of values)

3) 0.25 x N = # (this number is representative of the LOCATION of Q1 - count from bottom up)

4) use the same number from but count from top down - Q3)

5) subtract the numbers located at Q3 - Q1 to find IQR