Answer:
40.38 cents.
Step-by-step explanation:
In this case, the following formula must be applied:
z = (x-mean) / sd
sd is the standard deviation
If we reorganize, we are left with:
sd = (x-mean) / z
We know that 100 cents is 1 dollar, therefore 342 cents are $ 3.42, that is the value of the average. The value of "x" would be the one we want to compare with, it is $ 3.
z, we must look for it in the normal distribution table, we must look inside the table for the value of 0.15 (15%), which is the closest value, and they would be 0.1492, which corresponds to a value of z of -1.04.
Replacing all the values we are left with:
sd = (3.00-3.42) / - 1.04
sd = 0.4038
Therefore the standard deviation would be $ 0.4038 dollars or 40.38 cents.
