Eileen's Energy Bars has determined that an energy bar measuring 3.25 inches long has a z-score of +1 and an energy bar measuring 3.50 inches long has a z-score of +2. What is the standard deviation of the length of energy bars produced at Eileen's Energy Bars?

3.5
3.25
0.75
0.25

0.25

Step-by-step explanaition:

The z-score represents how many deviations a value is from the mean. When the bar measures 3.25, the z-score is +1. When the bar measures 3.50, the z-score is +2. You'll notice that whenever the bar size increases by 0.25, the z-score goes up +1. So, the standard deviation from the mean must be 0.25.

what is the original number? you forgot to add it.