Question

the mean is 15.2 and standard deviation is 0.9 find the probability that x is greater than 14.1?

the mean is 15.2 and standard deviation is 0.9 find the probability that x is between nd 16.6 ?

Answer 1

Solution :

Given that ,

mean = = 15.2

standard deviation = = 0.9

P(X >14.1 ) = 1 - P(x <14.1 )

= 1 - P((x - ) / < (14.1 - 15.2 ) / 0.9)

= 1 - P(z < -1.22)   Using standard normal table,

= 1 - 0.1112   

= 0.8888

Probability = 0.8888

Solution :

Given that ,

mean = = 15.2

standard deviation = = 0.9

P(X <16.6 ) = P(x <16.6 )

= P((x - ) / < ( 16.6 - 15.2) /0.9 )

= P(z < 1.56)   Using standard normal table,

=   0.9406   

Probability = 0.9406