In: Statistics and Probability
Question:A sociologist wishes to see whether the number of years of college a person has completed is related to their marital status. A sample of 1000 people over age 30 is selected and classified below. At ? = 0.05, can you conclude that years of college and marital status are Independent? Show all steps of the hypothesis test: Hypotheses, Alpha, Distribution, Sketch with Critical Value, Use StatCrunch to find Test Statistic and put on Sketch, Decision, Conclusion.
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null hypothesis: Ho: number of years of college a person has completed is not related to their marital status
alternate hypothesis:Ha: number of years of college a person has completed is related to their marital status
alpha =0.05
Distributionn is Chi square
for degree of freedom =(row-1)*(column-1)=(3-1)*(3-1) =4 and 0.05 level crtiical value =9.488
below is sketch for that:
applying chi square test of independence:
Observed | Oi | no college | college degree | graduate degree | Total |
never | 103 | 84 | 61 | 248 | |
married | 97 | 152 | 136 | 385 | |
divorced | 160 | 87 | 120 | 367 | |
Total | 360 | 323 | 317 | 1000 | |
Expected | Ei=?row*?column/?total | no college | college degree | graduate degree | Total |
never | 89.280 | 80.104 | 78.616 | 248 | |
married | 138.600 | 124.355 | 122.045 | 385 | |
divorced | 132.120 | 118.541 | 116.339 | 367 | |
Total | 360 | 323 | 317 | 1000 | |
chi square | =(Oi-Ei)2/Ei | no college | college degree | graduate degree | Total |
never | 2.108 | 0.189 | 3.947 | 6.245 | |
married | 12.486 | 6.146 | 1.596 | 20.227 | |
divorced | 5.883 | 8.392 | 0.115 | 14.391 | |
Total | 20.478 | 14.727 | 5.658 | 40.863 |
for above test satsitic =40.863
as test statistic falls in rejection region; we reject null hypothesis
we have sufficient evidence to conclude that number of years of college a person has completed is related to their marital status