1. Failure to meet payments on student loans guaranteed by the United States (U.S.) government has been a major problem for both banks and the government. Approximately 50% of all student loans guaranteed by the government are in default. A random sample of 350 loans to college students in one region of the U.S. indicates that 147 loans are in default.

b) Find a 99% confidence interval for the proportion of all student loans in the U.S. that are in default.

2. Suppose that the age of a randomly selected business major can be considered to be a random variable with a mean of 20 years and a standard deviation of 2 years. A group of 64 business majors is selected at random and their average age x

a) What is the approximate sampling distribution of xand why?

3. Suppose that the age of a randomly selected business major can be considered to be a random variable with mean 20 years and standard deviation 2 years. A group of 64 business majors is selected at random and their average age x}is calculated.

b) What is the probability that x< 19.7?

4. The following sample contains the scores of 6 students selected at random in Mathematics and English. Usethe scores in English as the dependent variable Y.

Mathematics score (X)	70	92	80	74	65	83
English score (Y)	74	84	63	87	78	90

x=464, y=476, x2=36354, y2=38254, xy=36926.

1. Estimate the regression parameters and also write the prediction equation.

5. The following sample contains the scores of 6 students selected at random in Mathematics and English. Usethe scores in English as the dependent variable Y.

Mathematics score (X)	70	92	80	74	65	83
English score (Y)	74	84	63	87	78	90

x=464, y=476, x2=36354, y2=38254, xy=36926.

b) Predict the English score for a student whose Mathematics score is 85.

6. The following sample contains the scores of 6 students selected at random in Mathematics and English. Usethe scores in English as the dependent variable Y.

Mathematics score (X)	70	92	80	74	65	83
English score (Y)	74	84	63	87	78	90

x=464, y=476, x2}=36354, y2=38254, xy=36926.

c) Find the sample correlation coefficient r and interpret.

7. The following sample contains the scores of 6 students selected at random in Mathematics and English. Usethe scores in English as the dependent variable Y.

Mathematics score (X)	70	92	80	74	65	83
English score (Y)	74	84	63	87	78	90

x=464, y=476, x2=36354, y2=38254, xy=36926.

d) Find the sample coefficient of determinationand interpret.