Wednesday!

Homework! More confidence intervals! I'm pumped!

Tonight, please complete the questions (about cheating on tests) provided in class!

If you lost the paper, the context and questions are provided below:

A Rutgers University study released in 2002 found that many high-school students cheat on tests. The researchers surveyed a random sample of 4500 high school students nationwide; 74% of them said they had cheated at least once.

a.) Create a 90% confidence interval for the level of cheating among high-school students. Assume the conditions for inference have been satisfied. You may use your graphing calculator to create your confidence interval, but still must show the formula with the appropriate values substituted)
b.) In a complete sentence, interpret your confidence interval from part a.
c.) A teacher surveys his students and finds that 68% of students have cheated on a test. Does this value seem reasonable? Surprising? Explain your reasoning.
d.) Suppose we sample 2,000 students and find that 67% have cheated. Calculate the margin of error.
e.) If we want to have a margin of error of only 3% and want 98% confidence, how large of a sample must be used?
f.) If we want to have a margin of error of 5% to create a 95% confidence interval, what is the appropriate sample size?

***Hint****
In some classes we did not (per E) get into the math for questions E and F. Here's what you need to consider--what is the margin of error (check your notes!)? Write down this formula for margin of error. In question e, we set this formula equal to 0.03. Then, we can substitute z*, p-hat = 0.5 and q-hat = 0.5, and do some algebra to solve for n.