In: Statistics and Probability
A sociologist who studies guns is interested in understanding
the differences in gun ownership across the United States,
particularly if there is a difference in number of guns owned per
household in Majority Republican States (n=18) vs. Majority
Democrat States (n=22). 10 states do not have a political lean.
(2018 data (Links to an external site.)).
Information |
Majority Republican States |
Majority Democrat States |
xbar |
1.2 guns |
0.5 guns |
Standard deviation |
0.1 |
0.2 |
number in sample |
18 |
22 |
Answer the following questions. While you are not asked to provide all of the information we have performed on the worksheets in class, following along with the worksheets will help you to answer this problem. Assume that you are performing a t-test at an alpha level of 0.05 (p<0.05).
A) What is the right t-test to use in this case: one-tailed or two-tailed? Why?
B) State your alternative and null hypotheses.
C) What is t-calculated?
D) What is t-critical?
E) Compare t-critical and t-calculated. What decision will you make: reject the null hypothesis, or reject the alternative hypothesis?
F) State your results in a complete sentence as described on the worksheet, including the mathematical portion. Explain what you can (and can’t) determine about the relationship between the variables at hand.
A)
Here, we want to test if there is a difference in number of guns owned per household in Majority Republican States v/s Majority Democrat States. Hence, here we are not intrested to know that which is inferior oe superior. We are only to know if there is any difference or not. So, the two-tailed t-test is best in this case.
B)
C)
Here,
Under , the test statistics is
Where
Now,
D)
E)
Since |t| calculated is more than t tabulated, So, the null hypothesis may be rejected at 5% level of significance and we may conclude that there is a difference in number of guns owned per household in Majority Republican States v/s Majority Democrat States.