Statistics
The Normal Density
February 10, 2009
Outline
1. Examples of normal distributions
(a) body temperature of college students: µ = 98.2, σ = .73
(b) 19 year old US males in 2000, height in inches: µ = 69.6, σ = 5.8
(c) LDL cholesterol levels of 20 year old females:
(d) Stanford-Binet IQ Test:
µ = 110, σ = 30
µ = 100, σ = 15
2. Finding proportions using the normal density
3. z-score (or standardized value)
4. Using Table A to find proportions
(a) proportion of individuals with IQ less than 115
(b) proportion of individuals with IQ greater than 115
(c) proportion of individuals with IQ between 80 and 120
(d) proportion of 19 year old males with height less than 6 feet (72 inches)
(e) proportion of 19 year old males between 5 feet and 6 feet
(f) the first quartile of LDL cholesterol of 20 year old females
Statistics
200
The Normal Density
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February 10, 2009
800
50
100
x
SAT scores
95
96
97
98
150
x
Cholesterol
99
x
Body Temperatures
100
101
−3
−2
−1
0
x
Standard Normal
1
2
3