Ryan is correct, the mean is about 8.1.
To find the mean, you have to add up all the values, then divide by the total amount.
For Sample A:
60 x 6 + 90 x 7 + 145 x 8 + 150 x 9 + 55 x 10 = 4050
If you add up all the adults, you have 500.
Dividing 4050 by 500 = 8.1
Sample B will produce a very similar result.
19/20
19/20 = 0.95
0.9 < 0.95
C) 2
1) Given the table, let's find out that missing data picking 2 points (2,-10) and (6,-4)
Since we have the slope, let's work on finding the linear coefficient
plugging point (2,-10) into that:
y= mx +b
-10 =3/2(2) +b
-10 =6/2 +b
-10= 3 +b
-10-3 =b
b= -13
2) So the rule of that function is y= 3/2x -13
Plugging x= 10 we have
y= 3/2(10) -13
y=2
3) So the missing y-coordinate is 2.