5 Steps to a 5 AP Psychology 2019

Research Methods ❮ 69

One

standard

deviation

Mean

mode

median

34.1%

13.6%

2.15% 2.15%

34.1%

99.7%

95.4%

68.2%

Scores

–3 –2 –1 0+1+2+ 3

55 70 85 100 115 130

200 300 400 500 600 700

145

800

0.01 2165084

(a)

(b) (c)

98 99.9

z Scores

Wechsler Adult

Intelligence Scale

SAT Math

Percentile

Mean

Mean

Median

Median

Low Scores High Scores Low Scores High Scores

Frequency (number of scores)

Frequency (number of scores)

13.6%

Figure 6.1 (a) The normal distribution or bell curve. (b) Negatively skewed distribution—skewed to
the left. (c) Positively skewed distribution—skewed to the right.