Assume that the sample is a simple random sample obtained from a normally distributed population of flight delays at an airport. Use the table below to find the minimum sample size needed to be 99% confident that the sample standard deviation is within 40% of the population standard deviation. A histogram of a sample of those arrival delays suggests that the distribution is skewed, not normal. How does the distribution affect the sample size? To be 95% confident that s is 1% within 5% 10% 20% 30% 40% 50% of the value of o, the sample size n should be at least 19,205 768 192 48 21 12 8 To be 99% confident that s is within 1% 5% 10% 20% 30% 40% 50% of the value of o, the sample size 33,218 1,336 336 85 n should be at least 38 22 14 The minimum sample size needed is