STATISTICAL。2

Questions

1) Do different airlines have different on-time performances?

Choose a set of 100 flights at random and calculate an ANOVA test of multiple means for the effect of carrier code on departure delay. Copy relevant Statgraphics output into your report and use α = 0.05.

Hint 1: To choose a set of 100 flights at random.

In Statgraphics: How to create a random sample using Statgraphics?

In Excel: How to create a random sample using Excel? Save this new spreadsheet as a new excel file and then load this file to Statgraphics: File > Open > Open Data Source > External Data File.

Hint 2: In Statgraphics, Compare > Analysis of Variance > One-way ANOVA.

Hint 3: After you obtain an ANOVA table using Statgraphics, double check to see whether the df (the last row of the ANOVA table) is 100 - 1 = 99. If not, it's likely that not 100 flights were selected.

2) Now repeat the above test, but treat the whole data file (Oregon Flight Data) as if it were a random sample of flights. You would use all flights (not 100 flights). Copy relevant Statgraphics output into your report and use α = 0.05. 

Hint 4: After you obtain an ANOVA table using Statgraphics, double check to see whether the df (the last row of the ANOVA table) is 4810 - 1 = 4809. If not, it's likely that not all Oregon flights were selected.

3) Compare your results for (1) and (2). Do they seem consistent? Why or why not?

4) Give your conclusion in statistical terms. What is the null hypothesis? Do we reject it? Why or why not?

5) Give your conclusion in everyday terms. Should I pay attention to which airline I’m flying, if I care about the delay in departure? Why or why not?