Questions 4

In a study by Radelet and Pierce (1991), the relationship between defendant’s ethnicity and sentencing to the death penalty over a 12 year period was investigated among 674 defendants convicted of murder in Florida. Only defendants and victims who were Caucasian or African-American were considered in the study results described in this question.

(a) Of the 483 Caucasian defendants, 53 were sentenced to the death penalty. Of the 191 AfricanAmerican defendants, 15 were sentenced to the death penalty.

State an appropriate null and alternative hypothesis for this study. Draw a suitable 2x2 contingency table to display these data and test at the 0.05 level (i.e. a = 0.05) for an association between defendant’s ethnicity and sentencing to the death penalty. Show your working, and present your conclusion with respect to your study hypotheses.

Radelet and Pierce also presented information concerning the ethnicity of the murder victim.

(b) There was a total of 515 Caucasian murder victims. Among the Caucasian victims, 467 defendants were also Caucasian. In these cases, there was a death penalty sentence for 53 defendants. The court determined that a total of 48 Caucasian victims were murdered by African-American defendants, and 11 of these defendants were sentenced to the death penalty.

State an appropriate null and alternative hypothesis for this component of the study concerned with Caucasian victims, clearly stating the population of interest. Create a suitable 2x2 table to display these data and test at the 0.05 level (i.e. a = 0.05) for an association between defendant’s ethnicity and sentencing to the death penalty. Show your working, and present your conclusion with respect to your study hypotheses.

(c) There was a total of 159 African-American victims. Among the African-American victims, 16 of the convictions were for Caucasian defendants, and no death penalties were sentenced for these defendants. Both defendant and victim were African-American for 143 convictions, and the death penalty was sentenced in 4 of these murders.

State an appropriate null and alternative hypothesis for this component of the study concerned with AfricanAmerican victims, clearly stating the population of interest. Create a suitable 2x2 table to display these data and test at the 0.05 level (i.e. a = 0.05) for an association between defendant’s ethnicity and sentencing to the death penalty. Show your working, and present your conclusion with respect to your study hypotheses.

(d) Comment on your conclusions across parts (a) – (c).