Question 329775
Perform a two-tailed test 
Null Hypothesis: Ho 
Alternative Hypothesis: H1

Ho: P=0.80
H1: p not 0.80
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Type of Test Statistic:
Z = (phat- P0)/sqrt(P0*(1-P0)/n)  where P0=population proportion under the null

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The Value of the Test Statistic: 
Phat = 193/235=0.821  SE=sqrt(P0*(1-P0)/n)= Sqrt(0.8*0.2/235)=0.026
Z=(0.821 -0.8)/0.026=0.808
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The two critical values at the 0.05 level of significance 
a two tail .05 critical area yields critical values -1.96, +1.96
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Can we conclude that the proportion of high school seniors who believe that "getting rich" is an important goal has changed? 

Since the test statistic is within the critical values (ie the region in which chance variations around the Hypothsized value resides) then we cannot reject Ho and thus the population proportion has not changed from 0.80