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For questions [link] – [link] , use the following information.
A new AIDS prevention drugs was tried on a group of 224 HIV positive patients. Forty-five (45) patients developed AIDS after four years. In a control group of 224 HIV positive patients, 68 developed AIDS after four years. We want to test whether the method of treatment reduces the proportion of patients that develop AIDS after four years or if the proportions of the treated group and the untreated group stay the same.
Let the subscript $t$ = treated patient and $\text{ut}$ = untreated patient.
The appropriate hypotheses are:
D
If the $p$ -value is 0.0062 what is the conclusion (use $\alpha =0.05\text{}$ )?
B
Lesley E. Tan investigated the relationship between left-handedness and right-handedness and motor competence in preschool children. Random samples of 41 left-handers and 41 right-handers were given several tests of motor skills to determine if there is evidence of a difference between the children based on this experiment. The experiment produced the means and standard deviations shown below. Determine the appropriate test and best distribution to use for that test.
Left-handed | Right-handed | |
Sample size | 41 | 41 |
Sample mean | 97.5 | 98.1 |
Sample standard deviation | 17.5 | 19.2 |
B
For questions [link] – [link] , use the following information.
An experiment is conducted to show that blood pressure can be consciously reduced in people trained in a “biofeedback exercise program.” Six (6) subjects were randomly selected and the blood pressure measurements were recorded before and after the training. The difference between blood pressures was calculated $\left(\text{after}-\text{before}\right)$ producing the following results: ${\overline{x}}_{d}=-\text{10}\text{.}2$ ${s}_{d}=8\text{.}4$ . Using the data, test the hypothesis that the blood pressure has decreased after the training,
The distribution for the test is
A
If $\alpha =0\text{.}\text{05}$ , the $p$ -value and the conclusion are
C
For questions [link] – [link] , use the following information.
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