To find the probability \( P(1.31 < Z < 2.15) \), we need to use the standard normal distribution table or a computational tool to find the cumulative probabilities for \( Z = 1.31 \) and \( Z = 2.15 \). The probability \( P(1.31 < Z < 2.15) \) is the difference between these two cumulative probabilities.
Step 1: Determine Cumulative Probabilities
To find \( P(1.31 < Z < 2.15) \), we first determine the cumulative probabilities for \( Z = 1.31 \) and \( Z = 2.15 \) using the standard normal distribution. The cumulative probability for \( Z = 2.15 \) is approximately 0.9842, and for \( Z = 1.31 \) it is approximately 0.9049.
Step 2: Calculate the Probability of the Range
The probability \( P(1.31 < Z < 2.15) \) is the difference between the cumulative probabilities for \( Z = 2.15 \) and \( Z = 1.31 \). Therefore, we calculate:
\[
P(1.31 < Z < 2.15) = 0.9842 - 0.9049 = 0.0793
\]
Final Answer
The probability \( P(1.31 < Z < 2.15) \) is \(\boxed{0.0793}\).