Variance Hypothesis
1. **State the problem:** We want to test if the standard deviation $\sigma$ of the golf professional's scores on his home course is equal to 1.20 (null hypothesis) against the alternative that it is not equal to 1.20 (two-tailed test).
2. **Given data:**
- Sample size $n = 10$
- Sample standard deviation $s = 1.32$
- Hypothesized population standard deviation $\sigma_0 = 1.20$
3. **Hypotheses:**
- Null hypothesis $H_0: \sigma = 1.20$
- Alternative hypothesis $H_a: \sigma \neq 1.20$
4. **Test statistic:** For testing variance or standard deviation, we use the chi-square test:
$$\chi^2 = \frac{(n-1)s^2}{\sigma_0^2}$$
5. **Calculate the test statistic:**
$$\chi^2 = \frac{(10-1) \times (1.32)^2}{(1.20)^2} = \frac{9 \times 1.7424}{1.44} = \frac{15.6816}{1.44} = 10.89$$
6. **Degrees of freedom:** $df = n - 1 = 9$
7. **Decision rule:** At a chosen significance level (commonly $\alpha = 0.05$), find critical values from chi-square distribution with 9 degrees of freedom. The null hypothesis is rejected if $\chi^2$ is less than the lower critical value or greater than the upper critical value.
8. **Interpretation:** Compare $\chi^2 = 10.89$ with critical values (approximately 2.7 and 19.0 for $\alpha=0.05$ two-tailed). Since $10.89$ lies between these values, we do not reject the null hypothesis.
**Final conclusion:** There is not enough evidence to conclude that the consistency (standard deviation) of his home course scores differs from 1.20.