According to a dietary study, high sodium intake may be related to ulcers, stomach cancer, and migraine headaches. The human requirement for salt is only 220 milligrams per day, which is surpassed in most single servings of ready-to-eat cereals. If a random sample of 20 similar servings of a certain cereal has a mean sodium content of 244 milligrams and a standard deviation of 24.5 milligrams, does this suggest at the 0.05 level of signicance that the average sodium content for a single serving of such cereal is greater than 220 milligrams? Assume the distribution of sodium contents to be normal.
Chapter 8 Notes – Surveys and Sampling Poll: What proportion of all registered voters in the state support the Affordable Care Act Would 1000 voters in Iowa or 1000 voters in NY provide a more accurate estimate (answer in lecture) Example: What percent of St. Cloud teenagers have a smart phone Unknowable so estimate it --- from a sample --- how to take the sample Is the estimate accurate What is the Population of interest All teenagers (13 – 19 years old) in St. Cloud What is the Parameter of interest (answer in lecture) What is the Sample (answer in lecture) What is the Statistic of interest (answer in lecture) How to take the sample (some answers in lecture) Suppose we go to the mall and interview teenagers. Why is that a bad idea