Respuesta :

Answer:

find the midpoint of each group, for the estimate

so it's

5,15,25,35,45,55

then multiply it by the frequency

to get

5,60,175,70,135,165

sum it, to get a total of 610

divide by the sum of the frequency (1+4+7+2+3+3)

610/20 =30.5 = mean