1. A recent study examined hearing loss data for 1,771 U.S. teenagers. In this sample, 333 were found to have some level of hearing loss. Your goal is to estimate the true long run proportion of all U.S teenagers who have some level of hearing loss.

1. Find the observed statistic (also called the point estimate) (1 pt).

1. Find the margin of error associated with the 95% confidence interval. (2 pts)

1. Construct a 95% confidence interval for the true long run proportion of all U.S. teenagers who have some level of hearing loss (2 pts).

1. Interpret the confidence interval in context (1pt).

Suppose we are interested in whether or 1 in 5 teens have hearing loss or not.

1. In symbols, state the correct hypotheses to test this claim (2 pts).

1. Based on your confidence interval above, would you reject or fail to reject the null hypotheses? Why? (2 pts)

1. What is the average time of a four-man Olympic Bobsleigh team? In the 2014 Sochi Olympics, the 27 finalist teams averaged 3.41 minutes with a standard deviation of 0.42.

1. Find the observed statistic (also called the point estimate) (1 pt).

1. Find the margin of error associated with the 95% confidence interval. (2 pts)

1. Construct a 95% confidence interval for the true long run average time of a four-man Olympic Bobsleigh team (2 pts).

1. Interpret the confidence interval in context (1 pt).

Suppose we are interested in whether an Olympic Bobsleigh team is slower than 3.5 minutes.

1. In symbols, state the correct hypotheses to test this claim (2 pts).

1. Based on your confidence interval above, would you reject or fail to reject the null hypotheses? Why? (2 pts)

1. A November 7-10, 2013, Gallup poll asked 1,039 U.S. adults how much they planned to personally spend on Christmas gifts this year. The report cited an average of $704, and the distribution is not strongly skewed.

1. State the parameter of interest in words. Assign a symbol (2 pts).

1. State the sample size and observed statistic (point estimate) with correct symbols (2 pts).

1. What does the symbol "" stands for?Do we know this value? (2 pts)

1. Are the validity conditions met? Justify (2 pts).

1. Calculate the 95% confidence interval when...
   1. and interpret this interval in context (2 pts).

1. and interpret this interval in context (2 pts).

1. Compare the standard error and confidence interval for e(i) and e(ii) (1 pt).

1. Suppose only 500 people were sampled and an average of $704 with sample standard deviation of $150.
   1. Calculate the 95% Confidence Interval (2 pts).

1. Compare the sample size and confidence intervals for e(i) and g(i) (1 pts).