Consider the following data set below. Find the UPPER INTERVAL of the population mean at 80\% confidence interval. Given: 12,10,9,11

UkusakazaL 2021-08-10 Answered
Consider the following data set below. Find the UPPER INTERVAL of the population mean at 80% confidence interval. (write your answer in two decimal places) Given: 12,10,9,11
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Answers (1)

question2answer
Answered 2021-08-16 Author has 155 answers

It is given that,
12,10,9,11
Thus,
Sample mean, x=t1nXtn=10.5
Sample standard deviation, s=t1n(XtX)2n1=1.29099
Since, Population standard deviation is unknown thus t distribution is used.
Sample size, n=4
Degree of freedom =n1=41=3
The value of tα2,n1 at 80% confidence interval is =1.638 [From t table]
Step 2
Now, the 80% confidence interval for the population mean can be calculated as:
CI=x±tα2,n1×sn
=10.5±1.638×1.290994
=(9.44,11.56)
Upper limit =11.56

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