Directions: Complete ALL of the following problems. Use an appropriate Calculator Program.

You may use either the or . The following formulas are provided for use or reference:

  1. The three leading manufacturers of peanut butter claim that a typical three-tablespoon serving of peanut butter contains about of fat and . To check on the accuracy of this claim, a random survey of , servings of peanut butter is taken. The sample results in an average of serving with a standard deviation . Assuming that the population is normally distributed, use a 5% level of significance to test the null hypothesis that the mean calorie content for the sample is the same as the calorie content claimed by the manufacturer.
  1. Government regulations require that when a sunscreen is labeled “waterproof,” then it must still work afterof immersion or carry claims of continuous protection after

to in the water. Manufacturers have responded by producing sunscreen lotions or creams with sun protection for at least of immersion. To check on this claim, the consumer’s group randomly selects 20 samples and finds that they still work an average of after immersion with a standard deviation of . Assuming that the population is normally distributed, use a level of significance to determine if we should reject the manufacturer’s claim about “waterproof”?

  1. A potato chip manufacturer packs bags of potato chips. The manufacturer wants the bags to contain, on the average, of potato chips. A quality-control engineer randomly selects a sample of 13 bags of potato chips and determines that the average weight of the bags is with a standard deviation of . Assuming that the population is normally distributed and using a 5% level of significance, should we reject the claim that the average bag contains of potato chips?
  1. The claim is that for nicotine amounts in king-size cigarettes, The sample size is and the test statistics is . Find the or range of .
  1. Listed below are speeds measured from southbound traffic on I-280 near Cupertino, California (based on date from SigAlert). This simple random sample was obtained at

3:30 P.M. on a weekday. Use a level of significance to test the claim that the sample is from a population with a mean that is less than the speed limit of

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