Question

1. The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.6 days and a standard deviation of 1.8 days.

Q: What is the probability of spending more than 2 days in recovery?

2. The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.5 days and a standard deviation of 2.2 days.

Q: What is the 70th percentile for recovery times?

3. A telephone poll of 1000 adult Americans was reported in an issue of a magazine. One of the questions asked was "[How much are] you worried about the quality of education in our schools?" Suppose 65% responded "a lot". We are interested in the population proportion of adult Americans who are worried a lot about the quality of education in our schools.

a) Define the Random Variables X and P', in words.

b) Which distribution should you use for this problem? (Round your answers to three decimal places.) P`~ and explain your choice.

c) Construct a 95% confidence interval for the population proportion of adult Americans who are worried a lot about the quality of education in our schools. State the confidence interval and sketch the graph. Also, calculate the error bound.

d) The sampling error given by the company which conducted the poll is ±3%. Explain what the ±3% represents.

Answer 1