Question

You are given the formula P(20 < x < 80) = 95%  Does this formula represent (please justify your answer):

A. the middle 95% of the standard normal distribution?

B. the middle 95% of a normal distribution?

C. the 95th percentile of a standard normal distribution?

D. the 95th percentile of the normal distribution?

Answer 1

$\mathbf{Solution}$

${\color{red} \mathbf{B.\; the \;middle\; 95\% \;of\; a\; normal\;distribution}}$

the middle 95% of the standard normal distribution is not the answer since it considers mean=0 and standard deviation=1.

95th percentile is the value to the left of the normal curve not in between as given the formula above in the problem