Assume that the sample is a simple random sample obtained from a normally distributed population of IQ scores of statistics professors. Use the table below to find the minimum sample size needed to be 99% confident that the sample standard deviation s is within 20% of o. Is this sample size practical? To be 95% confident that s is 1% 5% 10% 20% 30% 40% 50% within of the value of o, the sample size 19,205 768 192 48 21 12 8 In should be at least To be 99% confident that s is 5% 40% 50% within 1% 10% 20% | 30% of the value of o, the sample size n should be at least 33,218 1,336 336 85 38 22 14 The minimum sample size needed is