Question

In: Statistics and Probability

Between 20 and 25 violent acts are portrayed per hour on children’s TV. A study by...

Between 20 and 25 violent acts are portrayed per hour on children’s TV. A study by Johnson et al (2002) looked for links between TV viewing and aggression by following the TV viewing habits of children 1-10 years old. Of these, 88 watched < 1 hr TV per day, 386 watched 1-3 hrs and 233 watched > 3 hrs. Eight years later, researchers looked to see if any of the children had records of aggressive assaults on other people. The numbers of children with aggressive assaults were 5, 87 and 67 for each TV category, respectively. The remaining children were not aggressive.

Question 1: Create a contingency table of the results from the study. Carry out an appropriate statistical test to determine whether TV viewing is associated with future violence. What is the conclusion from your test?

Question 2: Do the results of the study prove that TV watching behavior causes increased aggression in children? Why?

Solutions

Expert Solution

Chi-Square Test of independence
Observed Frequencies
0
0 aggressive not aggressive Total
<1hours 5 83 88
1-3hours 87 299 386
<3hours 67 166 233
Total 159 548 707
Expected frequency of a cell = sum of row*sum of column / total sum
Expected Frequencies
aggressive not aggressive Total
<1hours 159*88/707=19.791 548*88/707=68.209 88
1-3hours 159*386/707=86.809 548*386/707=299.191 386
<3hours 159*233/707=52.4 548*233/707=180.6 233
Total 159 548 707
(fo-fe)^2/fe
<1hours 11.054 3.207
1-3hours 0.000 0.000
<3hours 4.0678 1.1802

Chi-Square Test Statistic,χ² = Σ(fo-fe)^2/fe =   19.510          
              
Level of Significance =   0.05          
Number of Rows =   3          
Number of Columns =   2          
Degrees of Freedom=(#row - 1)(#column -1) = (3- 1 ) * ( 2- 1 ) =   2          
              
p-Value =   0.0001   [Excel function: =CHISQ.DIST.RT(χ²,df) ]      
Decision:    p-value < α , Reject Ho          

so,
TV viewing is associated with future violence

.......................

results of the study prove that TV watching behavior causes increased aggression in children

as  TV viewing is associated with future violence

....................

Please revert back in case of any doubt.

Please upvote. Thanks in advance.


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