In all answers show your calculations (Except variance calculation). But full points will be given to the correct answer). The answers without the way of calculations will affect the grade.

Question 1) Point Interval estimation. Confidence Interval. (38%)

1. Assume that your dataset is a sample from the population, and each number refers to a daily expenditure of a given student. Now, I am interested in the population average i.e. mean expenditure of ADA students. However, the problem is I do not have the full population data. Use first nine observations in your data set and explain what is your estimator and estimate of the population mean? (4%)

1. Take the first nine observations in your dataset. Compute variance and standard deviation. No need to show calculation. The correct answer is enough. (4%)

1. It is suggested you build 90%, 95% and 99% confidence intervals for the population mean. Note that we do not know the standard deviation and you should use the answer in part b) above. Also provide comments on result you found in part (14%)

1. Explain what are the factors which affect Interval Estimate, referring your data set. Briefly discuss at least three of them (9%).

1. How many observations do I need to have the margin of error equal to 2 at 95% confidence level? (7%)

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