1.Assume that a sample is used to estimate a population mean

. Find the 95% confidence interval for a sample of size 62 with a mean of 79.9 and a standard deviation of 12.6. Enter your answer as anopen-interval(i.e., parentheses) accurate to one decimal place (because the sample statistics are reported accurate to one decimal place).

95% C.I. =

Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.

2.You measure 43 turtles' weights, and find they have a mean weight of 66 ounces. Assume the population standard deviation is 7 ounces. Based on this, what is the maximal margin of error associated with a 99% confidence interval for the true population mean turtle weight.

Give your answer as a decimal, to two places

ounces

3.You want to obtain a sample to estimate a population proportion. At this point in time, you have no reasonable estimate for the population proportion. You would like to be 99.9% confident that you esimate is within 0.2% of the true population proportion. How large of a sample size is required?

n=

Do not round mid-calculation. However, use a critical value accurate to three decimal places.

4.You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately =34.2

. You would like to be 99% confident that your esimate is within 2 of the true population mean. How large of a sample size is required?

n=

Do not round mid-calculation. However, use a critical value accurate to three decimal places this is important for the system to be able to give hints for incorrect answers.