You are a researcher studying the lifespan of a certain species of bacteria. a preliminary sample of 35 bacteria reveals a sample mean of ¯ x = 80 x ¯ = 80 hours with a standard deviation of s = 4.8 s = 4.8 hours. you would like to estimate the mean lifespan for this species of bacteria to within a margin of error of 0.65 hours at a 98% level of confidence. what sample size should you gather to achieve a 0.65 hour margin of error? round your answer up to the nearest whole number.