Answer :
A 90% confidence interval for the mean number of children in all household in this city is 1.12 ± 0.328, using formula for confidence interval.
What are mean and standard deviation ?
The standard deviation is a summary measure of the differences of each observation from the mean.
Formula to calculate confidence interval using mean and deviation:
mean ± Z*(std deviation/√n)
where n = sample size,
Given that :
mean = 1.12
deviation = 2.40
n = 144
We know Z is fixed for 90% confidence i.e. 1.64
So, the confidence interval = 1.12 ± 1.64*(2.4/√144)
= 1.12 ± 1.64 * .2
= 1.12 ± .328
Learn more about confidence interval using link :
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