Question

Kindergarten children have heights that are approximately normally distributed about a mean of 39 inches and a standard deviation of 2 inches. If a random sample of 19 is taken, what is the probability that the sample of kindergarten children has a mean height of less than 39.50 inches? (Round your answer to four decimal places.)

Answer 1

Solution :

Given that ,

mean =   = 39

standard deviation = = 2

n = 19

= 39

=  / n = 2/ 19=0.46

P( <39.50 ) = P[( - ) / < (39.50 - 39) /0.46 ]

= P(z <1.09 )

Using z table  

= 0.8621   

probability= 0.8621