\( X \) is a normally distributed random variable with mean 94 and standard deviation 22. What is the probability that \( X \) is between 46 and 96 ? Write your answer as a decimal rounded to the nearest thousandth.
Real Tutor Solution
Answer
Solution
Reviewed and approved by the UpStudy tutoring team
Beyond the Answer
To find the probability that \( X \) falls between 46 and 96, we first need to standardize these values using the Z-score formula: \[ Z = \frac{X - \mu}{\sigma} \] where \( \mu = 94 \) and \( \sigma = 22 \). 1. **Calculating the Z-scores**: - For \( X = 46 \): \[ Z_{46} = \frac{46 - 94}{22} = \frac{-48}{22} \approx -2.182 \] - For \( X = 96 \): \[ Z_{96} = \frac{96 - 94}{22} = \frac{2}{22} \approx 0.091 \] 2. **Using the Z-table or calculator**: - Find the probability associated with \( Z_{46} \) and \( Z_{96} \). - \( P(Z < -2.182) \approx 0.0145 \) (using a Z-table). - \( P(Z < 0.091) \approx 0.5360 \). 3. **Finding the probability between the two Z-scores**: \[ P(46 < X < 96) = P(Z < 0.091) - P(Z < -2.182) \approx 0.5360 - 0.0145 = 0.5215 \] Thus, the probability that \( X \) is between 46 and 96 is approximately \( \boxed{0.522} \) when rounded to the nearest thousandth.