SOLUTION: Find the sum of the areas under the standard normal curve to the left of z = -1.25 and to the right of z = 1.25. a. 0.1056 b. 0.7888 c. 0.2112 d. 0.3944

Algebra ->  Probability-and-statistics -> SOLUTION: Find the sum of the areas under the standard normal curve to the left of z = -1.25 and to the right of z = 1.25. a. 0.1056 b. 0.7888 c. 0.2112 d. 0.3944      Log On


   

Question 1143187: Find the sum of the areas under the standard normal curve to the left of z = -1.25 and to the right of z = 1.25.
a. 0.1056
b. 0.7888
c. 0.2112
d. 0.3944
Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!


The distribution is symmetrical, so find the z-score for -1.25 in your table and double it.

Note that, since 68% of data is between z=-1.0 and z=1.0, 32% is to the left of z=-1.0 or to the right of z=1.0. That makes answer choices b and d impossible; and a rough understanding of the normal distribution makes it easy to choose between answers a and c.