LowHigh Equal Distance Quantification Individual Differences

Interval & Ratio

1st 2nd 3rd 4th 5th Nominal Winners Tops Losers BottomOrdinal

M Md ModeMode Md M Mean Median Mode is unbiased, consistent and efficient estimate of µ Central Tendency & Skewness

Percentile is the value on a scale below which a given percentage of cases fall. 25 th percentile is called lower quartile. 75 th percentile is called upper quartile.

Average squared deviation from the mean Average deviation from the mean s 2 is unbiased, consistent, efficient estimate of σ 2 Variability (& Kurtosis) σ2σ2 σ2σ2 σ2σ2

Bar Chart

Line Chart

Box Plot + + +

Stem and Leaf Plot * ** HI20,33 Data Stem–and-Leaf Missing = 3

SB IQ T-score GRE, SAT Wechsler IQ Test of this course µ = 0, σ= 1 µ = 50, σ= 10 µ = 500, σ= 100 µ= 100, σ= 15 µ= 100, σ= 16 µ= 25, σ= 10 Linear Transformation & Standard Scores z-score

Normal Distribution

P (X > 1.64)

Area between -1 and -2

= 35, s = 5, % above

= 35, s = 5, % above

= 35, s = 5, % below

= 35, s = 5, % between 25 and –

= 35, s = 5, 95th percentile

= 35, s = 5, 75th percentile

CI

CI 95