Question: Write any 5-8 numbers between 1 and 40. They will represent sample data. Calculate Sample Mean ( x ) and Sample Standard Deviation (s). We
Write any 5-8 numbers between 1 and 40. They will represent sample data.
Calculate Sample Mean (x) and Sample Standard Deviation (s).
We don't know thevalue of population mean because we don't have data for the whole population.
But using this week study material we can predict/estimate interval that holds population mean:
x- is calculated sample mean,E is a Margin of Error.
This is the case when we don't know population standard deviation (case 2),
but we have calculated sample standard deviation (s).
Here is the formula for Margin of Error:
n - sample size (5,6,7,or 8).
ta/2is not tadivided by 2, it's just t-value from the Appendix Table
for t-distribution (t-Distribution.pdf) .
TheDegree of Freedomin this table is df = (n-1), sample size minus one.
Consider Confidence Level 90% (0.90).
Significance Level = 1 - Conf.Level = 1 - 0.90 = 0.10
To find ta/2in the Table for t-Distribution, use row with df=n-1
and the column withArea in Two Tailsequal 0.10.
Here are steps to follow:
1) Write 5-8 numbers between 1 and 40; this will be your sample data.
2) Calculate sample mean (x) and sample standard deviation (s).
3) Use Appendixt-Distribution.pdfto find t-value.
4) Calculate Margin of Error (E) using theformula above.
5) Write Confidence Interval for Population Mean:= x E
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