Question

Math SAT scores are Normally distributed with mean µ=500 and standard deviation σ=100 . The curve is displayed above. What percentage of the SAT Math scores are less than one standard deviation above the mean?

Answer 1

Explanation:

mean µ = 500

standard deviation σ = 100

Required P ( X < µ + σ )

= P ( X < 500 + 100 )

= P ( X < 600 )

= P [Z < (X - µ) / σ ]

= P [Z < (600 - 500) / 100 ]

= P [Z < + 1 ]

= .8413

In terms of percent the probability is 84.13 % .