Pyschology Statistics (Chapter 5)

Z-SCORE

a standard value that specifies the precise location of each X value (score) within a distribution

Z-score formula

(x - μ) / σ, individual data point - mean of the population/standard deviation of population

Raw score formula

X = μ + Zσ, individual data point = mean of the population + (Z-score x standard deviation)

Standardized Distribution

a distribution of scores that have been transformed to
create predetermined values for μ and σ

Shape of standardized distribution

the shape of a standardized distribution DOES NOT change from it’s original shape

The mean of the standardized distribution

It is always 0

Score of the standardized deviation

It is always 1

Positive Z-score

Data point is above average

Negative Z-score

Data point is below average

Find the standard deviation of a standardized distribution

σ = (x - μ) / z

Find the mean of a standardized distribution

μ = x - (z * σ)