Answer:
0.6915 is the required probability.
Step-by-step explanation:
We are given the following information in the question:
N(3.4, 3.1)
Mean, μ = 3.4
Standard Deviation, σ = 3.1
Formula:
We have to evaluate:

Evaluation of probability:
Calculation the value from standard normal z table, we have,
0.6915 is the probability that the percent change in worker output per hour from the previous quarter is more than 0.5 standard deviations below the mean.