Ratio Variances C735B2
1. **Problem Statement:**
Suppose we have two independent samples from two different populations. The first sample has variance $s_1^2 = 16$ with sample size $n_1 = 25$, and the second sample has variance $s_2^2 = 9$ with sample size $n_2 = 20$. Find the ratio of the two variances and interpret the result.
2. **Formula and Explanation:**
The ratio of two sample variances is given by:
$$ F = \frac{s_1^2}{s_2^2} $$
This ratio is often used in hypothesis testing (like the F-test) to compare the variability of two populations. A ratio greater than 1 indicates that the first sample has greater variance than the second.
3. **Calculation:**
Substitute the given values:
$$ F = \frac{16}{9} $$
Simplify the fraction:
$$ F = 1.777\ldots $$
4. **Interpretation:**
The ratio $F \approx 1.78$ means the variance of the first sample is about 1.78 times the variance of the second sample. This suggests the first population is more variable than the second.
**Final answer:**
$$ \boxed{\frac{s_1^2}{s_2^2} = \frac{16}{9} \approx 1.78} $$