Got it wrong , please help need an answer to this one

X Your answer is incorrect. Using the following information, determine the sample size needed if the standard time estimate is to be within 5 percent of the true mean 97 percent of the time. Mean Standard Observed Work Deviation Time Element (minutes) (minutes) 1 2 3 0.60 0.35 1.10 0.85 0.65 0.70 2.25 1.50 3.80 2.50 1.55 2.70 4 5 6 (Round up your answer to the whole number, e.g., 150.) Sample size needed is .294