Suupose you take sample of 25 high school students and measu

Suupose you take sample of 25 high school students and measure their IO\'s. Asumming that IQ is normally distributed with mean=100 and standard deviation=15 what is the probabilty that your samples IO will be 105 or greater?

Solution

using tables of Z distribution and the formula of standard Z

Z = ( xbar - miu ) / [ sigma / srqt(n) ]

P( x > 105)

P( z > (105-100) / [15 / srqt(25) ])

P( z> 1.67)

using tables to find that probability

P( z > 1.67) = 0.0475