Question

According to the children's growth chart the heights of two-year-old boys are normally distributed with a mean of 32.3 inches and a standard deviation of 1.4 inches. If a two-year-old boy is selected at random, what is the probability that he will be more than 34.2 inches tall?

Answer 1

Solution :

Given that ,

mean = = 32.3

standard deviation = = 1.4

n = 2

= 32.3

= / n = 1.4/ 2 = 0.99

P( > 34.2) = 1 - P( <34.2 )

= 1 - P[( - ) / < (34.2-32.3) /0.99 ]

= 1 - P(z <1.92 )

Using z table

= 1 - 0.9726

= 0.0274

probability= .0274