Question

Teen Court is a juvenile diversion program designed to circumvent the formal processing of first-time juvenile offenders within the juvenile justice system. An article reported on a study in which offenders were randomly assigned either to Teen Court or to the traditional Department of Juvenile Services method of processing. Of the 57 Teen Court individuals, 18 subsequently recidivated during the 18-month follow-up period, whereas 11 of the 54 Department of Juvenile Services individuals did so. Does the data suggest that the true proportion of Teen Court individuals who recidivate during the specified follow-up period differs from the proportion of Department of Juvenile Services individuals who do so

Answer 1

Answer:

Z-statistic = 1.4017 < 1.96 at 0.05 level of significance

Null hypothesis is accepted

The data suggest that the true proportion of Teen Court individuals who recidivate during the specified follow-up period differs from the proportion of Department of Juvenile Services individuals

Step-by-step explanation:

Step(i):-

Given first sample size (n₁ ) = 57

Of the 57 Teen Court individuals, 18 subsequently recidivated during the 18-month follow-up period

First sample proportion

                                   $p^{-} _{1} = \frac{x_{1} }{n_{1} } = \frac{18}{57} =0.3157$

Second sample proportion

                               $p^{-} _{2} = \frac{x_{2} }{n_{2} } = \frac{11}{54} =0.2037$

Null Hypothesis : p₁⁻ = p₂⁻

Alternative Hypothesis :  p₁⁻ ≠ p₂⁻

Step(ii):-

Test statistic

         $Z = \frac{p_{1} ^{-} -p^{-} _{2} }{\sqrt{PQ(\frac{1}{n_{1} } +\frac{1}{n_{2} } )} }$

        where

                   $P = \frac{n_{1}p^{-} _{1} +n_{2} p^{-} _{2} }{n_{1} +n_{2} }$

                   

              $P = \frac{57 X0.3157+0.2037X54}{54+57} = 0.2612$

             Q = 1 - P = 1 - 0.2612 = 0.7387

         

             $Z = \frac{0.3157-0.2037}{\sqrt{0.2612 X0.7387 (\frac{1}{57} +\frac{1}{54} )} }$

           Z  =    1.4017

Level of significance ∝ =0.05

The tabulated value Z₀.₀₅ = 1.96

Z-statistic = 1.4017 < 1.96 at 0.05 level of significance

Null hypothesis is accepted

The data suggest that the true proportion of Teen Court individuals who recidivate during the specified follow-up period differs from the proportion of Department of Juvenile Services individuals