1. What is a sampling distribution and what does it show?

2. What is the difference between a parameter and a statistic and how do they relate to each other?

3. The Pew Research Center interviewed n=755 US cell phone users age 18 and older in May 2011 and found that the average number of text messages sent or received per day is 41.5 messages, with a standard error about 6.1

a. State the population and parameter of interest. Use the information from the sample to give the best estimate of the population parameter

b. Find and interpret a 95% confidence interval for the mean number of text messages.

4. Explain the process to generate a bootstrap distribution by giving an example.

5. What is the difference between a p-value and a confidence interval? How are each used to interpret data?

6. Go to http://lock5stat.com/statkey/ . Under bootstrap confidence interval for the difference in proportions find the data "Use text messages (by age)". Generate a bootstrap dot plot of 5000 samples (taking 800 values with replacement from the original teen sample and 2252 from the adults)

a. Print out your dot plot

b. What is the 95% confidence interval using the percentile method?

c. Calculate the standard error

d. Using the standard error from part (c), find and interpret the 95% confidence interval for the difference in proportion of teen and adult cell phone users who send/receive text messages.

7. Arsenic-based additives such as Roxarsone in chicken feed is still mixed in the diet of about 70% of the 9 billion broiler chickens produced annually in the US. Although 500 ppb are allowed, one restaurant will cancel a supplier if the sample provides sufficient evidence that the average amount of arsenic in chicken provided by that supplier is greater than 80 ppb. a. Define the population parameter

b. State the null and alternative hypotheses

c. Go to http:filock5stat.comistatkey/ . Under Randomization Hypothesis Tests, Test for Single Mean find the data for "Arsenic in Chicken". Generate 2000 samples. Choose left tail, two tail or right tail that corresponds to your hypothesis in part (b) and find the p-value.

d. Print the Dot Plot.

e. Is there enough evidence to reject the null hypothesis? (Interpret the p-value in the context of the problem.)