The time required to finish a test in normally distributed with a mean of 80 minutes and a standard
deviation of 15 minutes. What is the probability that a student chosen at random will finish the test in more
than 95 minutes?
A. 82%
B. 2%
C. 34%
D. 16%

Question

The time required to finish a test in normally distributed with a mean of 80 minutes and a standard 
deviation of 15 minutes. What is the probability that a student chosen at random will finish the test in more
than 95 minutes?
A.		 82%
B.		 2%
C.		 34%
D.		 16%

anonymous · Answer

Find the $z$ score first. $$
z =\frac{x-\mu }{\sigma }=\frac{95-80}{15}=1
$$

anonymous · Answer

http://www.wolframalpha.com/input/?i=z+score+1

anonymous · Answer

It says the right tailed value (probability that is it above 95) is $\approx 0.1587$
That makes $16\%$ a very good contender here.

anonymous · Answer

thank you