Distribution Model A smooth representation of the distribution of ALL individuals in the POPULATION. -3 -2 -1 1 2 3 4 Quantitative Value 10 20 30 40 50 Frequency Normal Distributions

Distribution Model Useful for estimating the proportion of individuals within a particular range of values (e.g., X < -1). -3 -2 -1 1 2 3 4 Quantitative Value 10 20 30 40 50 Frequency Normal Distributions

s m Normal Distribution Most important distribution model Infinite number, but each is … bell-shaped centered on m dispersion of s x ~ N(m,s) s m Quantitative Value Normal Distributions

N(m,s) s m m-s m+s m-3s m-2s m+2s m+3s Quantitative Value Normal Distributions

N(10,4) 4 -2 2 6 10 14 18 22 Quantitative Value Normal Distributions

N(0,1) 1 -3 -2 -1 1 2 3 Quantitative Value Normal Distributions

N(10,4) -2 2 6 10 14 18 22 Quantitative Value Normal Distributions