In which of the following situations would you use the Chi-squared test for inde
ID: 3292347 • Letter: I
Question
In which of the following situations would you use the Chi-squared test for independence? Indicate by Yes or No, and if No, explain. (a) A farmer wants to know if there is an association between amount of fertilizers and infestation by crop pests. She had 100 plots of land and assigned one of 3 levels of fertilizers, "Low" "Medium" and "High" to each plot. Right before the harvest, in each plot of land she checked whether that plot of land had been infested by crops pests or not. (b) Researchers are interested if age of a child is associated with onset of Type II diabetes. They measured the ages of 1500 children and tested them for the presence/absence of Type II diabetes. (c) Researchers are interested if age of a child is associated with onset of Type II diabetes. They measured the ages of 1500 children as "Toddler", "Child", "Preteen", "Teen" and tested then for the presence/absence of Type II diabetes. (d) There is an interest in whether air pollution increases after the 4th of July every year. Scientists measured the air pollution one day before and a day after July 4th in 50 cities in United States and categorized that city as "Increase in Pollution" or "No increase in Pollution.Explanation / Answer
(a) Yes, Chi Square test for independence can be used.
(b) Age of children vs presence/absence of diabetes ;
as the age variable is not categorized, we cannot form a contingency table and carry out the chi square test for independence.
(c) Yes
(d) No. The data cannot be put in a contingency table to test for independence.