In: Statistics and Probability
Suppose the Federal Aviation Administration (FAA) would like to compare the on-time performances of different airlines on domestic, nonstop flights. The following table shows two different airlines and the frequency of flights that arrived early, on-time, and late for each. To test at the 0.1 level to determine if Airline and Status are dependent, calculate the chi-square test statistic and p-value.
Chart:
26 14 16
16 22 6
Question 4 options:
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Solution:- (4) 7.37, the degrees of freedom is 2, and the p-value is 0.0251.
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
H0: Airline and Status are dependent are
independent.
Ha: Airline and Status are dependent are not
independent.
Formulate an analysis plan. For this analysis, the significance level is 0.10.
Analyze sample data. Applying the chi-square test for independence to sample data, we compute the degrees of freedom, the expected frequency counts, and the chi-square test statistic. Based on the chi-square statistic and the degrees of freedom, we determine the P-value.
DF = (r - 1) * (c - 1) = (2 - 1) * (3 - 1)
D.F = 2
Er,c = (nr * nc) / n
Χ2 = 7.37
where DF is the degrees of freedom.
The P-value is the probability that a chi-square statistic having 2 degrees of freedom is more extreme than 7.37.
We use the Chi-Square Distribution Calculator to find P(Χ2 > 7.37) = 0.0251
Interpret results. Since the P-value (0.025) is less than the significance level (0.10), we cannot accept the null hypothesis. Thus, we conclude that there is a relationship between Airline and Status.