Math 140 Activity #2 Null and Alternative Hypothesis For each of the following problems: a) Write the null and alternative hypothesis. b) Label whether the null or the alternative is the original claim. c) Tell whether this is a left tail test, a right tail test, or a two tail test. 1. According to a CNN report, besides cell phones, 93% of Americans also own a traditional phone. But has that percentage decreased as more and more Americans opt to only use a cell phone and throw away their traditional phones? 2. According to a recent Newspaper article, people in California spend 1.25 hours a day eating and drinking. Suppose we want to test the claim that the number of hours spent eating and drinking is really 1.25 hours. 3. More and more Americans are becoming financially sound and opting to not own a credit card. According to an article in USA Today, 74% of Americans still have at least one credit card. But this claim seems a little on the low side. We think that more than 74% of Americans own a credit card. 4. It has long been thought that normal body temperature is really 98.6 degrees Fahrenheit. A recent study is now claiming that normal body temperature is really lower than 98.6 degrees. 5. The standard deviation for the heights of men was thought to be 2.9 inches. New studies disagree with this. Test the claim that the standard deviation for heights of men is not 2.9 inches. 6. Wikipedia suggests that at least 10% of the world population is left handed. Wikipedia may not be very accurate. Test the claim that at least 10% of the world population is left handed. 7. The percent of women that hold CEO level jobs is lower than the percent of men that hold CEO level jobs. 8. The average cholesterol level for American men and women is about the same. 9. The majority of Republicans support decreasing taxes. Hypothesis Test Notes Test Statistics
Write the null and alternative hypothesis. Is this a right tailed, left tailed or two tailed test? Check whether the problem meets the assumptions necessary to perform the hypothesis test. List all the assumptions and how the problem meets the assumptions or does not meet the assumptions. Use Statcrunch and the information given in the problem to calculate the z test statistic. Write a sentence explaining the meaning of the test statistic. Use Statcrunch and the information given in the problem to calculate the P-value. Write a sentence explaining the meaning of the P-value. State whether you reject or fail to reject the null hypothesis and then write the conclusion for the hypothesis test. The United States has the highest rate in the industrialized world. In 2008 a random sample of 1014 teenage girls found that 326 of them were pregnant before the age of 20. Has the proportion of teenage pregnancy increased as of 2012? In 2012, a random sample of 1025 teenage girls was taken and 334 were found to be pregnant before the age of 20. (Use a 10% significance level.) While many Americans favor the legalization of marijuana, opponents of legalization argue that marijuana may be a gateway drug. They believe that if a person uses marijuana, then they are more likely to use other more dangerous illegal drugs. Use the table of random data given below to test the claim that marijuana users have a higher percentage of other drug use than non-marijuana users. (Hint: Use a 5% significance level.) Uses Other Drugs Total Uses Marijuana 87 213 Does not use Marijuana 26 219