PROBLEM 1: As you increase your sample size, what happens to your confidence interval? Why?

PROBLEM 2: As you increase your alpha, what happens to the confidence interval? Why?

PROBLEM 3: When we convert a normal distribution into a standard normal distribution, we convert the data such that the mean is zero and the standard deviation is one. Starting with the equation that brings about this transformation, derive the equation we use to calculate the confidence interval.

PROBLEM 4: Suppose we are testing whether toothpaste bottles are filled with the advertised amount of toothpaste. When were analyzing a sample of tubes, why does a test statistic greater than a positive critical value (or less than a negative critical value) mean that you reject the null hypothesis?

PROBLEM 5: A company manufactures kitten mittens for people that need a quieter cat. A random sample of 121 cats is taken. The sample mean noise from a cats step is 5.5 decibels with a standard deviation of 0.6 decibels. Construct a 99% two-sided confidence interval estimate for cat noise.

PROBLEM 6: The Daily Grind Coffee Company sells a machine that creates a cup of coffee that should be 12 oz. If its less, the customer will be mad; if its more, the cup will overflow. If , X = 12.90 ounces, and s = 1.20 ounces, test the companys claim at a .05 significance level using the appropriate test.

PROBLEM 7: The Bluth Company claims its Cornballers have an average life of at least 10 years. With = .02, use the appropriate method to test this claim. ; X = 9.8 years; s = 1.1 years.

PROBLEM 8: A researcher samples 49 bouncy castles and finds: X = 6 years; s = 0.90 years. Construct a 95% confidence interval.

PROBLEM 9: Subway Sandwiches wants to know if the average salary of its sandwich artists is really $340. They dont want them to earn too little, but they dont want to bankrupt the company, either. They take a sample of 64 artists and finds that X =$300 and s = $80.

• Using the appropriate method, test their hypothesis at = 0.05.
• Are we at risk or committing a Type I or Type II error?
• Construct a 95% confidence interval of

PROBLEM 10: Turbo Testosterone claims that people using its workout supplement will gain at least 8 pounds of solid bulk muscle. ; .5 pounds, .8 pounds

• Use the following sample to test at = .05.
• Are we at risk or committing a Type I or Type II error?
• Suppose the company is thinking of making a claim using a 95% two-sided confidence interval. Construct the interval using the same data and suggest the maximum claim the company can make.