The area between z= -2.31 and z= 0.47

0.67038

Explanation:

One z-value is negative and the other is positive.

This means we are looking for area between the two given z-values on opposite sides of the mean.

From z-table attached, the area at z = -2.31 is 0.98956

Also, from the second z-table attached, the area at z = 0.47 is 0.68082

But since we are looking for the area between both z-scores, we will now have;

P(-2.31 < x < 0.47) = (0.98956 + 0.68082) - 1

P(-2.31 < x < 0.47) = 0.67038

the histogram that represents the data with the largest spread is data set b