Question

If X has a normal distribution with mean µ = 11 and variance σ2  = 16, find the value of x if P (X < x) = 0.8186.

	A	2.9
	B	14.6
	C	12.6
	D	17.9

Answer 1

Given that,

mean = = 11

standard deviation = = 16=4

Using standard normal table,

P(Z < z) =0.8186

= P(Z < z) = 0.8186  

= P(Z <0.91 ) = 0.8186

z = 0.91 Using standard normal table,

Using z-score formula  

x= z * +

x= 0.91*4+11

x= 14.6