TABLE 6-4 According to Investment Digest, the Arithmetic Mean of the Annual

question 140

Short Answer

TABLE 6-4
According to Investment Digest, the arithmetic mean of the annual return for common stocks from 1926-2010 was 9.5% but the value of the variance was not mentioned. Also 25% of the annual returns were below 8% while 65% of the annual returns were between 8% and 11.5%. The article claimed that the distribution of annual return for common stocks was bell-shaped and approximately symmetric. Assume that this distribution is normal with the mean given above. Answer the following questions without the help of a calculator, statistical software, or statistical table.
-Referring to Table 6-4, find the two values that will bound the middle 80% of the annual returns.

---

Definitions:

Chi-Square Statistic

Statistic that tests the difference between the distribution of observed frequencies and expected frequencies.

Expected Frequencies

The theoretical counts of occurrences across different categories or within bins that one would expect if the data followed a specific statistical distribution.

Chi-Square Statistic

A statistical measure used to determine the significance of the difference between observed and expected frequencies in categorical data.

Expected Frequencies

The anticipated count of occurrences in each category of a variable, calculated based on a theoretical distribution in the context of hypothesis testing.