Question

22 wrong results, 74 correct results

.05 significance level

polygraph correct less than 80% of time

test statistic and p value

Answer 1

Ho :p = 0.8     

H1 :p <0.8 (Left tail test)

  

Level of Significance,α = 0.05

Number of Items of Interest,x =74

Sample Size,n =22+74 = 96

  

Sample Proportion , p̂ = x/n = 0.7708

  

Standard Error , SE = √( p(1-p)/n ) = 0.0408

Z Test Statistic = ( p̂-p)/SE = (0.7708-0.8) /0.0408 =    -0.7144

p-Value=0.2375               [excel function =NORMSDIST(z)]