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Two portfolios were randomly assembled from the NY Stock Exchange, and daily stock prices were shown. At α = 0.05, can it be concluded that there is a difference in variances of the two portfolios? Find the coefficient of variation. Portfolio A: 36.44, 44.21, 12.21, 59.6, 55.44, 39.42, 51.29, 48.68, 41.59, 19.49. Portfolio B: 32.69, 47.25, 49.35, 36.17, 63.04, 17.74, 4.23, 34.98, 37.02, 31.48.

User Hguser
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Final answer:

To test for a difference in variances between two portfolios, we can perform a hypothesis test using the F-test. If the p-value is less than the significance level (α = 0.05), we reject the null hypothesis and conclude a difference in variances. The coefficient of variation can be calculated by dividing the standard deviation of a portfolio by its mean and multiplying by 100.

Step-by-step explanation:

To test whether there is a difference in variances of the two portfolios, we can perform a hypothesis test using the F-test. The null hypothesis, H0, is that the variances are equal, while the alternative hypothesis, Ha, is that the variances are different.

  1. H0: The variances of the two portfolios are equal.
  2. Ha: The variances of the two portfolios are different.

We can calculate the p-value using the F-test statistic and compare it to the significance level, α = 0.05, to make a decision. If the p-value is less than α, we reject the null hypothesis and conclude that there is a difference in variances. If the p-value is greater than or equal to α, we fail to reject the null hypothesis and do not have enough evidence to conclude a difference in variances.

After finding the p-value, we can find the coefficient of variation by dividing the standard deviation of the portfolio by its mean and multiplying by 100. The coefficient of variation is a measure of relative variability and helps compare the variation between two or more sets of data.

The coefficient of variation can be calculated as:

CV = (standard deviation / mean) x 100

User Guy Goldstein
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