Question

(4) 0.5 =
%
(A) 75
(B) 5
(C) 50
(D) 25​

Answer 1

Answer:

This is a classic example of finding mean and standard deviation using Z values.

From this page find the Z value corresponding to 31% area under the curve and 92% (100-8) percent area under the curve.

Math Is Fun Virtual Manipulative

Note: You'll probably be given tables to lookup in your quizzes.. they're a bit confusing. But you might as well learn how to use it.

As you know:

Z=X−μσZ=X−μσ

Put in X and Z values values twice, you'll have two linear equations. Solve them and the answer is yours!

Answer 2

We know a % = a/100

• In our case We need to Find a

0.5 × 100 = a %

⇒ 50 = a %

∴ Correct Answer is Option (C)