Trials in an experiment with a polygraph include results that include cases of wrong results and cases of correct results. Use a significance level to test the claim that such polygraph results are correct less than % of the time. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, conclusion about the null hypothesis, and final conclusion that addresses the original claim. Use the P-value method. Use the normal distribution as an approximation of the binomial distribution.

Trials in an experiment with a polygraph include 97 results that include 23 cases of wrong results and 74 cases of correct results. Use a 0.01 significance level to test the claim that such polygraph results are correct less than 80% of the time. Identify the nullhypothesis, alternative hypothesis, test statistic, P-value, conclusion about the null hypothesis, and final conclusion that addresses the original claim. Use the P-value method. Use the normal distribution as an approximation of the binomial distribution.

The computation is shown below:

The null and alternative hypothesis is

[tex]H_0 : p = 0.80[/tex]

[tex]Ha : p < 0.80[/tex]

[tex]\hat p = \frac{x}{ n} \\\\= \frac{74}{97}[/tex]

= 0.7629

Now Test statistic = z

[tex]= \hat p - P0 / [\sqrtP0 \times (1 - P0 ) / n][/tex]

[tex]= 0.7629 - 0.80 / [\sqrt(0.80 \times 0.20) / 97][/tex]

= -0.91

Now

P-value = 0.1804

[tex]\alpha = 0.01[/tex]

[tex]P-value > \alpha[/tex]

So, it is Fail to reject the null hypothesis.

There is ample evidence to demonstrate that less than 80 percent of the time reports that these polygraph findings are accurate.