To find the highest and lowest 32% of grade averages in a normal distribution:
Given:
\mu = 2.58
\sigma = 0.45
1. **Calculate the z-score for the 68th percentile:**
z = 0.47
2. **Convert this z-score to an actual grade point average for the highest 32%:**
x = \mu + (z \times \sigma)
x = 2.58 + (0.47 \times 0.45)
x = 2.58 + 0.2115
x = 2.7915
Thus, the highest 32% of grade point averages are above:
x > 2.7915
3. **Calculate the z-score for the 32nd percentile:**
z = -0.47
4. **Convert this z-score to an actual grade point average for the lowest 32%:**
x = \mu + (z \times \sigma)
x = 2.58 + (-0.47 \times 0.45)
x = 2.58 - 0.2115
x = 2.3685
Thus, the lowest 32% of grade point averages are below:
x < 2.3685
**Summary:**
- The highest 32% of grade point averages lie above:
x > 2.7915
- The lowest 32% of grade point averages lie below:
x < 2.3685
**Answer:**
- \text{Highest 32\%: } x > 2.7915
- \text{Lowest 32\%: } x < 2.3685