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Has the Percentage of U.S. Adults Who Smoke Decreased since 2007? With data from the 2005-2007 National Health Interview Survey, the Centers for Disease Control and Prevention estimated that about 20% of U.S. adults (18 and older) smoke. Is the percentage lower this year? Suppose we select a random sample of 100 adults (18 and older) this year. The conditions are met for use of a normal model, because we expect 20 smokers (20% of 100) in the sample and 80 nonsmokers. Both expected counts are greater than 10, so we use a z-score and a standard normal curve to assess the evidence. (The standard error is 0.04.) Suppose that 15 in our sample of 100 are smokers. Which conclusion is supported by the data? We cannot conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. We can conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. Incorrect. You are right that the percentage in the sample is 15% and this is less than 20%. But the Z-score is -1.25. So this sample result is not unusual. There is about a 10.6% chance that random * samples of 100 adults will have 15% or fewer smokers if 20% of all adults smoke. This sample could have come from a population in which 20% smoke. We conclude that the percentage of smokers in the population is not less than 20%

Has the Percentage of U.S. Adults Who Smoke Decreased since 2007? With data from the 2005-2007 National Health Interview Survey, the Centers for Disease Control and Prevention estimated that about 20% of U.S. adults (18 and older) smoke. Is the percentage lower this year? Suppose we select a random sample of 100 adults (18 and older) this year. The conditions are met for use of a normal model, because we expect 20 smokers (20% of 100) in the sample and 80 nonsmokers. Both expected counts are greater than 10, so we use a z-score and a standard normal curve to assess the evidence. (The standard error is 0.04.) Suppose that 15 in our sample of 100 are smokers. Which conclusion is supported by the data? We cannot conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. We can conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. Incorrect. You are right that the percentage in the sample is 15% and this is less than 20%. But the Z-score is -1.25. So this sample result is not unusual. There is about a 10.6% chance that random * samples of 100 adults will have 15% or fewer smokers if 20% of all adults smoke. This sample could have come from a population in which 20% smoke. We conclude that the percentage of smokers in the population is not less than 20%

MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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Has the Percentage of U.S. Adults Who Smoke Decreased since 2007? With data from the 2005-2007 National Health Interview Survey, the Centers for Disease Control and Prevention estimated that about 20% of U.S. adults (18 and older) smoke. Is the percentage lower this year? Suppose we select a random sample of 100 adults (18 and older) this year. The conditions are met for use of a normal model, because we expect 20 smokers (20% of 100) in the sample and 80 nonsmokers. Both expected counts are greater than 10, so we use a z-score and a standard normal curve to assess the evidence. (The standard error is 0.04.) Suppose that 15 in our sample of 100 are smokers. Which conclusion is supported by the data? We cannot conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. We can conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. Incorrect. You are right that the percentage in the sample is 15% and this is less than 20%. But the Z-score is -1.25. So this sample result is not unusual. There is about a 10.6% chance that random * samples of 100 adults will have 15% or fewer smokers if 20% of all adults smoke. This sample could have come from a population in which 20% smoke. We conclude that the percentage of smokers in the population is not less than 20%
Transcribed Image Text:Has the Percentage of U.S. Adults Who Smoke Decreased since 2007? With data from the 2005-2007 National Health Interview Survey, the Centers for Disease Control and Prevention estimated that about 20% of U.S. adults (18 and older) smoke. Is the percentage lower this year? Suppose we select a random sample of 100 adults (18 and older) this year. The conditions are met for use of a normal model, because we expect 20 smokers (20% of 100) in the sample and 80 nonsmokers. Both expected counts are greater than 10, so we use a z-score and a standard normal curve to assess the evidence. (The standard error is 0.04.) Suppose that 15 in our sample of 100 are smokers. Which conclusion is supported by the data? We cannot conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. We can conclude that the percentage of U.S. adults (18 and older) who smoke is less than 20% this year. Incorrect. You are right that the percentage in the sample is 15% and this is less than 20%. But the Z-score is -1.25. So this sample result is not unusual. There is about a 10.6% chance that random * samples of 100 adults will have 15% or fewer smokers if 20% of all adults smoke. This sample could have come from a population in which 20% smoke. We conclude that the percentage of smokers in the population is not less than 20%
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