Answer:
Independence chi-square test
Step-by-step explanation:
The Chi-Square Test for independence is a type of statistical hypothesis test that is used to determine the existence of an association or relationship between nominal or categorical variables
The chi-square is given by the following formula;

The number of participants = 80
The number that assigned a verdict of guilty = 27
The number that assigned a verdict of not guilty by reason of self defense = 49
The number that assigned a verdict of not guilty by reason of insanity = 4
Independence Chi Square test
The table of values is presented as follows;
Expected Value = (Row sum * Column Sum)/(Grand Total)
Expected Value for Guilty = 27 × 80/80 = 27
Expected Value for Self Defense = 49 × 80/80 = 49
Expected value for Insanity = 4 × 80/80 = 4

We have m(<CBO) = (1/2) · m(<CBE) = (1/2) · ( x + z );
In the same way, m(<BCO) = (1/2) ·( x + y);
m(<BOC) = 180 - [(1/2) · ( x + z ) + (1/2) ·( x + y)] = 180 - (1/2)· ( x + x + y + z );
But, x + y + z = 180;
Then, m(<BOC) = 180 - (1/2)·( x + 180 );
Finally, m(<BOC) = 90 - (1/2)·x;
So, m(<BOC) = 90 - (1/2)·m(<BAC).
-16 + 4x = 20
+16 +16
———————
4x= 36
————
4
x= 9