Haze weather statistics

(1) 20.5% of the citizens participated in the survey = 400 people.

m=60400= 15%，n= 1-5%-45%- 15%=35%。

So the answer is: 400, 15%, 35%.

(2) The central angle corresponding to the sector in Part D of the sector statistical chart is 360× 35% = 126.

So the answer is: 126.

(3) The number of people in Part D is 400×35%= 140 (people).

As shown in figure 1,

Xiao Ming touched a white ball.

There are two red balls and two white balls in it.

∴ Xiao Gang randomly finds another ball from the remaining four balls. The probability of a white ball and a red ball is 12.

The probability of Xiao Ming participating in the competition is 12.