Aset of data is normally distributed with a mean of 455 and a standard deviation of 25. what percent of the data is in the interval 405–455? a. 47.5% c. 68.3% b. 49.85% d. 34.15%

From the problem, we can say that it is a normal deviation so we should use the normal distribution curve.

First, calculate the z-score of the intervals 405 and 455.
SD = 25
Mean = 455

z-score = (x-mean)/SD
z-score of 405 = (405-455)/25 = -2
z-score of 455 = (455-455)/35 = 0

The z-score of 0, 0 is 0.5 and the z score of -2, 0 is 0.0228.

So to get the percentage, subtract 0.5 with 0.0228
0.5 - 0.0228 = 0.4772
Convert 0.4772 to percent
= 47.72%

Closest to 47.72 % is letter A.

The answe may be c