Does secondhand smoke increase the risk of a low weight birth? A baby is “low birth weight” if it weighs less than 5.5 pounds at
birth. According to the National Center of Health Statistics, about 7.8% of all babies born in the U.S. are categorized as low birth weight. Researchers randomly select 1200 babies whose mothers had extensive exposure to secondhand smoke during pregnancy. 10.4% of the sample are categorized as low birth weight. Which of the following are the appropriate null and alternative hypotheses for this research question. H 0 : p = 0.078; H a : p ≠ 0.078 H 0 : p = 0.078; H a : p > 0.078 H 0 : p = 0.104; H a : p ≠ 0.104 H 0 : μ = 0.104; H a : μ > 0.104
The researchers say that the rate is about 7.8%, or 0.078 as a decimal. That makes that the null hypothesis because using "is" in math is the same as saying "equals" and the null hypothesis always has the statement of equality in it. The reason there is a not equals to sign in the alternate is for this reason as well. The researchers say it is about that amount, not more or less than that amount. So it makes this a 2 tailed test. If the amount is significantly higher or lower, then we might have to reject the null hypothesis depending on the outcome of the test.
