1. A researcher studying the lifespan of a certain species ofbacteria. A preliminary sample of 35 bacteria reveals a sample meanof ¯ x = 64 x ¯ = 64 hours with a standard deviation of s = 5.6 s =5.6 hours. He would like to estimate the mean lifespan for thisspecies of bacteria to within a margin of error of 0.5 hours at a98% level of confidence. What sample size should you gather toachieve a 0.5 hour margin of error? He would need to samplebacteria.
2. For a confidence level of 98% with a sample size of 26, findthe critical t value. Critical Value = (round answer to 3decimal places)
3. Assume that a sample is used to estimate a population mean??. Find the 80% confidence interval for a sample of size 31 with amean of 85.9 and a standard deviation of 6.3. Enter your answeraccurate to one decimal place. I am 80% confident that the mean ??is between (blank) and (blank)
4. Assume that a sample is used to estimate a population mean??. Find the 95% confidence interval for a sample of size 34 with amean of 81.3 and a standard deviation of 16.8. Enter your answeraccurate to one decimal place.
I am 95% confident that the mean ?? is between (blank) and(blank)
