
Explanation:
Explanation:
This is an F-test for comparing two variances. The correct approach is:
Hypothesis formulation: Since we suspect the insurance industry earnings are MORE divergent (greater variance) than banking, we test:
Test statistic calculation:
F-statistic = s₁² / s₂² = (4.8²) / (4.3²) = (23.04) / (18.49) = 1.2461
Critical value and decision:
Matching with options:
Therefore, Option I is correct.
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Justin Heinz, FRM, suspects that the earnings of the insurance industry are more divergent than those of the banking industry. In a bid to confirm his suspicion, Heinz collects data from a total of 31 insurance companies and establishes that the standard deviation of earnings across that industry is $4.8. Similarly, he collects data from 41 banks and establishes that the standard deviation of earnings across that industry is $4.3. Conduct a hypothesis test at the 5% level of significance to determine if the earnings of the insurance industry have a greater standard deviation than those of the banking industry.
| Choice | Hypothesis | Test statistic | Decision |
|---|---|---|---|
| I. | H₀: σ₁² ≤ σ₂² <br> H₁: σ₁² > σ₂² | 1.2461 | Earnings are statistically not significant from one another |
| II. | H₀: σ₁² ≤ σ₂² <br> H₁: σ₁² > σ₂² | 1.74 | Earnings are statistically not significant from one another |
| III. | H₀: σ₁² ≤ σ₂² <br> H₁: σ₁² ≤ σ₂² | 1.2461 | Earnings are statistically significant from one another |
| IV. | H₀: σ₁² ≤ σ₂² <br> H₁: σ₁² < σ₂² | 1.74 | Earnings are statistically not significant from one another |
A
I
B
II
C
III
D
IV