Steve is a painter. He can paint a house in 20 hours. It takes his assistant 30 hours to paint a house. How long, in hours, woul
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<h2>Answer with explanation:</h2>
When the sample size is small (< 30) and the population standard deviation is unknown , then we use t-test.
The confidence interval for population mean will be :
(1)
, where = sample mean
t* = Critical value (based on degree of freedom and significance level).
s= sample standard deviation
n= sample size.
As per given we have
n= 9
Degree of freedom = n-1 = 8
s= 0.75
Significance level =
Using students' t distribution table ,
Critical value :
We assume that the population is approximately normal.
Then, a 80% confidence interval for the mean waste recycled per person per day for the population of Florida will be :
(Substitute the values in (1))
Hence, the 80% confidence interval for the mean waste recycled per person per day for the population of Florida. = (2.047, 2.753)