Test the proportions of yellow fire trucks have a significantly lower accident rate.

In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of yellow fire trucks made 135,035 runs and had 4 accidents. At   = .01, did the yellow fire trucks have a significantly lower accident rate?
(a) Declare the hypotheses.
(b)State the decision rule and sketch it.
(c)Find out the sample proportions and z test statistic.
(d)Make a decision.
(e)Find out the p-value and interpret it.
(f)If statistically significant, do you think the difference is large enough to be important? If so, to whom, and why?
(g)Is the normality assumption fulfilled? describe.