If the standard deviation of return on the stocks of the S&P/TSX Composite Index has been
approximately 24% per year over the last decade, it must be true that half of the ﬁrms in the index
have a standard deviation of return below 24% over the same period.

Question

Quizplus · Accepted Answer

We cannot assume that half of the firms in the index have a standard deviation of return below 24% just because the overall index has had a standard deviation of 24%. The standard deviation of individual firms' returns may vary widely from the overall index.

If the Standard Deviation of Return on the Stocks of the S&P/TSX