In: Statistics and Probability
With 90% confidence, for sample mean 334.00, sample standard deviation 10.40, and sample size 35, what is the upper confidence limit with 2 decimal places?
Solution :
Given that,
Point estimate = sample mean = = 334.00
Population standard deviation =
= 10.40
Sample size = n =35
At 90% confidence level the z is
= 1 - 90% = 1 - 0.90 = 0.1
= 0.1
Z = Z0.1 = 1.28 ( Using z table )
Margin of error = E = Z
* (
/n)
=1.28 * (10.40 / 35
)
=2.2501
At 90% confidence interval estimate of the population mean
is,
+ E
334.00 +2.2501
336.2501
upper limit=336.2501