In: Statistics and Probability
Are the educational aspirations of students related to family income? This question was investigated in the article “Aspirations and Expectations of High School Youth” (Int. J. of Comp. Soc. (1975): 25). The accompanying 4 X 3 table resulted from classifying 273 students according to expected level of education and family income. Does the data indicate that education aspirations and family income are not independent? Conduct hypothesis test using = .05. Income Aspired Level Low Middle High Some High School 9 11 9 High School Graduate 44 52 41 Some College 13 23 12 College Graduate 10 22 27
null hypothesis:Ho: education aspirations and family income are independent
alternate hypothesis:Ha: education aspirations and family income are not independent
degree of freedom(df) =(rows-1)*(columns-1)= | 6 |
for 6 df and 0.05 level of signifcance critical region χ2= | 12.592 | 12.592 |
applying chi square test:
Expected | Ei=row total*column total/grand total | Low | middle | High | Total |
Some HS | 8.0733 | 11.4725 | 9.4542 | 29 | |
HS grad | 38.1392 | 54.1978 | 44.6630 | 137 | |
Some college | 13.3626 | 18.9890 | 15.6484 | 48 | |
College grad | 16.4249 | 23.3407 | 19.2344 | 59 | |
total | 76 | 108 | 89 | 273 | |
chi square χ2 | =(Oi-Ei)2/Ei | Low | middle | High | Total |
Some HS | 0.1064 | 0.0195 | 0.0218 | 0.148 | |
HS grad | 0.9006 | 0.0891 | 0.3004 | 1.290 | |
Some college | 0.0098 | 0.8472 | 0.8506 | 1.708 | |
College grad | 2.5132 | 0.0770 | 3.1352 | 5.725 | |
total | 3.530 | 1.033 | 4.308 | 8.8709 |
from above as test statistic X2 =8.871 is not in rejection region we can not reject null hypothesis
we do not have evidence at 0.05 level to conclude that education aspirations and family income are not independent