Respuesta :
I think the group 2 survey is likely to be biased towards people who are not too keen on zoos since all the values are small.
From group 1 and 3 the mean number of visits are
(4 + 10 + 6 + 3 + 8 + 7 + 9 + 3 + 4 + 7) / 10
= 61/10
mean = 6
From group 1 and 3 the mean number of visits are
(4 + 10 + 6 + 3 + 8 + 7 + 9 + 3 + 4 + 7) / 10
= 61/10
mean = 6
Group 2 is biased.
mean number of visits = (4+10+6+3+8+7+9+3+4+7)/10 = 61/10 = 6.1
mean number of visits = (4+10+6+3+8+7+9+3+4+7)/10 = 61/10 = 6.1