Solutions HWB03

2.8:

Five number summary:

Minimum 3.1

Q1 (6.0+6.2)/2 = 6.1
Median (7.1+7.1)/2 = 7.1

Q3 (8.0+8.7)/2 = 8.35

Maximum 10.5

Box plot:

2.10:

x f xf
2 1 2
6 4 24
8 3 24
10 2 20
13 2 26
sum: 12 96


x-bar = 96/12 = 8

2.16:

x f xf dev=(x - x-bar) f(dev)^2
2 1 2 2-8 = -6 1(-6)^2 = 36
6 4 24 6-8 = -2 4(-2)^2 = 24
8 3 24 8-8 = +0 3(+0)^2 = 0
10 2 20 10-8 = 2 2(+2)^2 = 8
13 2 26 13-8 = 5 2(+5)^2 = 50
sum: 12 96 sum: 118

Variance = 118/11 = 10.727273
SD = sqrt[variance] = 3.275

SE = SD/sqrt[n] = 3.275/sqrt[12] = 0.9455