An investor is trying to decide whether to invest in a given stock, but is worried about the volatility of the investment. If the investor is very certain that the volatility (as measured by the standard deviation) is greater than 16% then the investor will choose a different investment option. In a sample of the previous 81 days reveals that the standard deviation of the investment is 20%. When testing the hypothesis (at the 1% level of significance) that the standard deviation is higher than 16%, what is the test statistic? (be careful on this) (please round your answer to 2 decimal places)