1. Explain why it is important to calculate a confidence interval when we do not have data from the entire population.

2. Explain the meaning of the term "90% confidence" in the following scenario without using the word "confident" or "confidence" in the part you must add. You are measuring the length of fish in a pond and want to know the mean length of the population of fish. You must begin your explanation with "Assume I have data from 100 samples of fish taken from the pond. The 90% confidence interval communicates that...." (finish the idea)

3. For a fixed level of confidence, what happens to a confidence interval forwhen we increase the sample size?

4. Suppose that for a sample size of n=150, we find that the sample mean is 88. Assuming that the standard deviation = 5.5, calculate the confidence intervals for the population meanwith the following confidence levels.

a. 90%

b. 92%

c. 95%

d. 97%

e. 99%

5. Compare the t curve to the z curve. What is each used for?What are their similarities and differences?