In: Math
In a simple random sample of 100 households, the sample mean number of personal computers was 1.32. Assume the population standard deviation is 0.41. Construct a 95% confidence interval for the mean number of personal computers.
(a) (1.24, 1.40)
(b) (1.25, 1.39)
(c) (0.15, 0.67)
(d) (0.19, 0.63)
Solution :
Given that,
Point estimate = sample mean =
= 1.32
Population standard deviation =
= 0.41
Sample size = n = 100
At 95% confidence level
= 1 - 95%
= 1 - 0.95 =0.05
/2
= 0.025
Z/2
= Z0.025 = 1.96
Margin of error = E = Z/2
* (
/n)
= 1.96 * ( 0.41 / 100
)
= 0.08
At 95% confidence interval estimate of the population mean is,
- E <
<
+ E
1.32 - 0.08 <
< 1.32 + 0.08
(1.24 <
< 1.40)
(1.24, 1.40)
correct option is = a)