Answer:
mean weight = 70.6 Kg
Explanation:
mean is calculated as
mean =

From the stem and leaf plot , using the data for men with Key 4/2 = 42
sum for stem of 6
= 4(65) + 2(66) + 67 + 68 + 2(69)
= 260 + 132 + 67 + 68 + 138
= 665
sum for stem of 7
= 72 + 2(73) + 2(74) + 2(75) + 76 + 77 + 78
= 72 + 146 + 148 + 150 + 76 + 77 + 78
= 747
Then total sum = 665 + 747 = 1412
the count ( number of men ) = 20
Then
mean =
= 70.6 Kg