Question 127710This question is from textbook
: Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study, researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the inactive pill. (a) State the apporporiate hypotheses. (b) Ovtain a test statistic and p-value. Interpret the results at level of significance .01. (c)is normality assured? (d) Is the difference large enough to be important? (e) What else would medical researchers need to know before prescribing this drug widely?
This question is from textbook
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study, researchers gave lovastatin to 2,325 people
and an inactive substitute to 2,081 people (average age 58).
After 5 years, 57 of the lovastatin group had suffered a heart attack,
compared with 97 for the inactive pill.
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(a) State the appropriate hypotheses.
Ho: p(inactive) - P(active) =0
Ha: p(inactive) - p(active) > 0
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p-hat(inactive) = 97/2081 = 0.0466
p-hat(active) = 57/2325= 0.0245
If you pool the data you get p-bar = (97+57)/(2081+2325) = 0.0350
and q-bar = 1-p-bar = 0.9650
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alpha = 1%; critical value = z = 2.326
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(b) Obtain a test statistic and p-value.
z(0.0466-0.0245) = (0.0221)/sqrt[(0.035*0.965/2081)+(0.035*0.965/2325)]
3.9849
p-value - 0.0000338
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Interpret the results at alpha = .01
Because the p-value is less than alpha, reject Ho; there is significant
statistical evidende that the application of the medicine reduces the
incidence of death.
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(c) Is normality assured?
2081*0.035= 72.84 > 5 and 2081*0.965 >5
2325*0.035=70.86 > 5 and 2325*0.965 >5
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(d) Is the difference large enough to be important?
The p-value gives very strong evidence that for the truth of Ha.
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(e) What else would medical researchers need to know before prescribing this drug widely?
I'll leave that to you.
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Cheers,
Stan H.
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