1. **State the problem:** Calculate the z-score for the measurements 34.6, 35.6, and 37.2 using the formula $$z = \frac{x - \bar{x}}{s}$$ where $\bar{x}$ is the mean and $s$ is the standard deviation.
2. **Calculate the mean $\bar{x}$:**
$$\bar{x} = \frac{34.6 + 35.6 + 37.2}{3} = \frac{107.4}{3} = 35.8$$
3. **Calculate the standard deviation $s$:**
First, find the squared differences from the mean:
$$ (34.6 - 35.8)^2 = (-1.2)^2 = 1.44 $$
$$ (35.6 - 35.8)^2 = (-0.2)^2 = 0.04 $$
$$ (37.2 - 35.8)^2 = (1.4)^2 = 1.96 $$
Sum these squared differences:
$$ 1.44 + 0.04 + 1.96 = 3.44 $$
Divide by $n-1 = 2$ (sample standard deviation):
$$ \frac{3.44}{2} = 1.72 $$
Take the square root:
$$ s = \sqrt{1.72} \approx 1.311 $$
4. **Calculate each z-score:**
For $x=34.6$:
$$ z = \frac{34.6 - 35.8}{1.311} = \frac{-1.2}{1.311} \approx -0.915 $$
For $x=35.6$:
$$ z = \frac{35.6 - 35.8}{1.311} = \frac{-0.2}{1.311} \approx -0.153 $$
For $x=37.2$:
$$ z = \frac{37.2 - 35.8}{1.311} = \frac{1.4}{1.311} \approx 1.068 $$
5. **Final answer:**
The z-scores are approximately:
- For 34.6: $-0.915$
- For 35.6: $-0.153$
- For 37.2: $1.068$
Z Score Calculation D47089
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