Shargrodosky, Curhan, Curhan, and Eavey(2010)studied whether hearing loss among teens has increased. The researchers compared a random sample of 2928 teens from a 1994 study to a random sample of 1771 teens from a 2006 study . In the 1994 study, 480 teens had hearing loss while in the 2006 study, 333 had hearing loss. The researchers are trying to estimate the difference in the two populations,
. The researchers tested the hypotheses
They calculated a p-value=0.0343 and Z=2.12 and designated
. Answer the following questions using this information.
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Select all of the following statements that are correct.
A clinical study conducted in the early 1990s recruited 324 pregnant women who were HIV-positive. The researchers believe that the pregnant women taking AZT will have fewer babies born HIV-positive. Of the 164 women who were randomly assigned to use the experimental (at the time) drug AZT, 13 had HIV-positive babies. Of the 160 women who were randomly assigned to receive a placebo, 40 had HIV-positive babies. The data has been summarized in the following table. Use this information to answer the following questions.
|AZT mothers||Placebo mothers||ROW TOTAL|
|not HIV-positive baby||151||120||271|
|COLUMN TOTAL||164||160||n = 321|
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Is this study an observational study or an experiment?
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Identify all of the parameters for this study.
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Write out the null and alternative hypotheses for this study.
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Are the validity conditions satisfied for this study?
A random selection of married couples from Joliet, IL were asked to state how much TV they watched in the week of June 2 to June 8, 2019. The researchers are trying to determine if there is any difference in the TV watching habits between married couples. A matched pairs design was used and for each couple the difference (Wife – Husband) was calculated for each couple. The sample summary statistics and boxplots of the data are presented below.
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State the null and alternative hypotheses.