1. a. = 53

b. = 3.95

2. a. = 34

b. = 1.922

3. Answers given to 1 decimal place.

 

Population mean

Population standard deviation

sample size

Mean of sample means

Variance of sample means

Standard deviation of sample means
Question
(μ)
(σ)
(n)
a
85
12
100
85
1.4
1.2
b
30
5
16
30
1.5625
1.25
c
5.6
5.5
25
5.6
1.2
1.1
d
23
21.2
50
23
9
3
e
230
240
400
230
144
12

4. a. σ = 3b. = 20 and = 0.3 5. 
Mean life of light bulbs is 2000 hours. 
Standard deviation of light bulbs 1100 hours.6. 
The number of houses in the sample should be 250.