Question

Suppose a variable X is normally distributed with a standard deviation of 10. Given that 30.85% of the values of X are greater than 70, what is the mean of X?

Answer 1

so Z=(70-mu)/10, and P(X>Z)=30.85%, solve for mu?

Answer 2

any illustrations ?

Answer 3

nope, thatsall of the question from our textbook

Answer 4

k

Answer 5

ok, so (70-mu)/10=invNorm(30.85%)

Answer 6

sorry, invnorm(1-.3085)

Answer 7

k, so here is a standard deviation formula