Assume that X has a normal distribution with a mean 17 and

Assume that X has a normal distribution, with a mean = 17, and standard deviation =3. Find P(7 < X < 18).

Solution

mean = 17,

standard deviation =3

P(7 < X < 18) = P( (7 - 17)/3 < Z < (18 - 17)/3 )

= P( -3.333 < Z < 0.333)

= P(Z < 0.333) - P(Z < -3.333)

= 0.6305 - 0.0004

= 0.6301

P(7 < X < 18) = 0.6301