In: Statistics and Probability
We learned this week that a chi-square analysis has requirements for variables that are unique from the other analyses we've considered. For instance, the variables must be exhaustive, so they must include all possible answers. For this reason, something like yes and no are valid since those would be the only two options, unless you had someone who couldn't answer it for various reasons. Similarly, it needs to be mutually exclusive, so someone couldn't be in two categories at the same time. This should make sense as you want to see if there's a relationship between the variables and you need to compare the expected counts with the actual counts. This is a very unique kind of test as you're only able to see categories - you wouldn't be able to tell if someone was at the high or low end of a category, for instance. Therefore, while it provides a quick and easy way to see if there are general differences, you don't necessarily know how extreme the situations are. Do you feel it's more important to have the quick and easy categorical results, or have the more detailed numerical results, and why?
Answer:
The Chi Square measurement is usually utilized for testing connections between absolute factors. The invalid speculation of the Chi-Square test is that no relationship exists on the clear cut factors in the populace; they are independent.
How does the Chi-Square statistic work?
Calculating the Chi-Square statistic and comparing it against a critical value from the Chi-Square distribution allows the researcher to assess whether the observed cell counts are significantly different from the expected cell counts.
The calculation of the Chi-Square statistic is quite straight-forward and intuitive:
where
fe = the expected frequency if NO relationship existed between the variables
fo = the observed frequency (the observed counts in the cells)
Here
In such cases, increasingly point by point numerical outcomes
are significant as one of the fundamental assumption of
Chi-Square is that the measurement of estimate of the
considerable number of factors is nominal or ordinal.
Along these lines, if an value is at the high or low end
of a class then Chi Square Test should not be utilized
for such cases.