The specific solution is as follows: (1) sort out the calculated data. ① Determine the population median value xi of yield per mu. It is 250,550,650,750,850 in turn. ② Determine xi frequency = mu/ total mu. 20/200, 30/200, 50/200, 60/200, 40/200.

(2) Calculate statistical indicators.

① Average output x' = ∑ xi * (fi) = 250 * 0.1+550 * 0.15+650 * 0.25+750 * 0.3+850 * 0.2 = 665.

(2) The mode number is the number with the highest frequency. Majority =750. ③ The median is the middle number. Median =650.

④ Variance D(x)=∑(Xi-x')? fi=(250-665)？ *0. 1+…+(850-665)? *0.2=28275。 ∴ standard deviation δ = √ [d (x)] =168.1517. ⑤ standard deviation coefficient = standard deviation/average value = δ/x' =168.1517/665 = 25.29%.

For reference.