It would be really nice if someone could help me out and suggest me with his expert opinion.
Going through the table and looking at Part (a) of this question. I believe I should use Scatter plot to prove that there is a change from 2000 to 2001.
On X-Axis I can use Line Length (Miles) and on Y-Axis # of faults. Am i doing it correct?
For Part (b) I am planning to use y= Alpha + BetaX equation and regression co-efficient (R) formula to find out correlation (Highly correlated etc) but I don't know how to find out probable limits on 95% confidence. Please help me here and tell me whether my plan is right.
For Part (c) How to test hypothesis? even if I am not using hypothesis looking at scatter plot and regression equations I can prove that Alpha is not equal to 0.
Please help. Thank you in advance..
It asks about faults per mile. To get that you need to divide the number of faults by the number of miles. A scatterplot would put the year on the $x$-axis and the number of faults per mile on the $y$-axis.
You could just do a two-sample $t$ test, where the two populations are the two years.
Or an anova with year as the predictor and faults per mile as the response variable. You could also see if adjusting for region and then doing that anova makes a difference.