12 Which of the following statements concerning areas under

12. Which of the following statements concerning areas under the standard normal curve is/are true?

A. If a z-score is negative, the area to its right is greater than 0.5

B. If the area to the right of a z-score is less than 0.5, the z-score is negative.

C. If a z-score is positive, the area to its left is less than 0.5

a. A

b. A, C

c. A, B

d. B, C

Solution

We know that the area on each side of the mean (i.e. = 0) in a standard normal distribution curve is = 0.5.

So, if the Z-score is negative, it means the value lies on the left side of the mean. Hence, the area to the right will be greater than 0.5.

Now, if the area to the right of a Z-value is less than 0.5 that means, the Z-value lies on the right hand side of the central value. So, Z-score must be positive.

If the Z-score is positive, then it lies right of the central value and hence, the area to its left will be more than 0.5.

So, only option A is correct.

So, answer is - a)A