Question

“Criminologists have long debated whether there is [an association] between weather and violent crime. The author of the article "Is There a Season for Homicide?" (Criminology (1988): 287 - 296) classified [1352] homicides according to season, resulting in the accompany data.”
Results of the author’s study found the following counts of homicide in the population studied.
• winter = 311
• spring = 320
• summer = 401
• fall = 320
Does it appear that homicide counts differ by season? You must identify the correct analysis and present results in APA style.

Answer 1

Chi square test for Goodness of fit  
  
expected frequncy,E = expected proportions*total frequency  
total frequency=   1352

observed frequencey, O	expected proportion	expected frequency,E			(O-E)²/E
311	0.250	338.00			2.157
320	0.250	338.00			0.959
401	0.250	338.00			11.743
320	0.250	338.00			0.959

chi square test statistic,X² = Σ(O-E)²/E =   15.817

Ho: homicide counts do not differ by season

H1: homicide counts differ by season

chi square test statistic,X² = Σ(O-E)²/E =   15.817              
                  
level of significance, α=   0.05              
Degree of freedom=k-1=   4   -   1   =   3
                  
P value =   0.0012   [ excel function: =chisq.dist.rt(test-stat,df) ]          
Decision: P value < α, Reject Ho                  

there is enough evidence to conclude that homicide counts differ by season