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.
