Which one of the following statements is correct concerning the standard deviation of a portfolio? Standard deviation used to determine the amount of risk premium that should apply to a portfolio. The standard deviation of a portfolio is equal to a weighted average of the standard deviations of the individual securities held within the portfolio. The greater the diversification or a portfolio, the greater the standard deviation of that portfolio The standard deviation of a portfolio is equal to the geometric average standard deviation of the Individual securities held within that portfolio The standard deviation or a portfolio can often be lowered by changing the weights of the securities in the portfolio