Respuesta :
Answer: i think i got b or c onr of them are correct :)
Step-by-step explanation:
The estimated population mean with
80% confidence = [30.856, 33.135]
90% confidence = [30.543, 33.456]
98% confidence = [29.94, 34.06]
What is confidence interval?
For a population with unknown mean and known standard deviation , a confidence interval for the population mean, based on a simple random sample of size n, is [tex]\bar x +_{-}z^{*}\frac{\sigma}{\sqrt{n} }[/tex] , where z* is the upper (1-C)/2 critical value for the standard normal distribution.
Population standard deviation = 5.6
Sample mean = 32
Sample size = 40
Given confidence level = 80%
[tex]z^{*}[/tex] at 80% confidence level = 1.28
Upper confidence interval = 33.135
Lower confidence interval = 30.865
Population mean lies between [30.856, 33.135] at 80% confidence level.
Given confidence level = 90%
[tex]z^{*}[/tex] at 90% confidence level = 1.65
Upper confidence interval =33.456
Lower confidence interval = 30.543
Population mean lies between [30.543, 33.456] at 90% confidence level.
Given confidence level = 98%
[tex]z^{*}[/tex] at 98% confidence level = 1.65
Upper confidence interval = 34.06
Lower confidence interval = 29.94
Population mean lies between [29.94, 34.06] at 98% confidence level.
Learn more about confidence interval here
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