Z Score Heights F51661
1. **Problem Statement:**
We have a population of student heights normally distributed with mean $\mu=168$ cm and standard deviation $\sigma=5.0$ cm.
We need to find z-scores for heights 175 cm and 164 cm, find the percentage of students between these heights, and find the percentage taller than 175 cm.
2. **Formula for z-score:**
$$z=\frac{X-\mu}{\sigma}$$
where $X$ is the value, $\mu$ is the mean, and $\sigma$ is the standard deviation.
3. **Calculate z-score for 175 cm:**
$$z=\frac{175-168}{5}=\frac{7}{5}=1.4$$
4. **Calculate z-score for 164 cm:**
$$z=\frac{164-168}{5}=\frac{-4}{5}=-0.8$$
5. **Find percentage between 164 cm and 175 cm:**
Look up the cumulative probabilities for $z=1.4$ and $z=-0.8$ in the standard normal table or use a calculator.
- $P(Z<1.4) \approx 0.9192$
- $P(Z<-0.8) \approx 0.2119$
Percentage between = $0.9192 - 0.2119 = 0.7073$ or 70.73%
6. **Find percentage for heights 175 cm or more:**
This is $P(Z \geq 1.4) = 1 - P(Z < 1.4) = 1 - 0.9192 = 0.0808$ or 8.08%
**Final answers:**
- a) $z=1.4$
- b) $z=-0.8$
- c) Approximately 70.73% of students have heights between 164 cm and 175 cm.
- d) Approximately 8.08% of students have heights 175 cm or more.