( 1)∵.0.25? ? ? . =0.25,.0. 17? ? ? . =0. 17,.？ 0.30? ? ? . =0.30.+0.03? ? ? . =0.03,.？ 0.25? ? ? . =0.25,

0.30>0.25>0. 17>0.03,

The most standard ball weight: 5+0.03=5.03 (g)

Minimum standard weight: 5-0.30=4.70(g),

A: The most standard badminton weighs 5.03g, and the least standard badminton weighs 4.70g:

(2) The weight of these five shuttlecocks: (0.25+0.17-0.30+0.03-0.25)+5× 5 = 24.9 (g),

The average weight of each badminton: 24.9÷5=4.98(g),

Answer: These five shuttlecocks weigh 24.9 grams, with an average weight of 4.98 grams.