Formulas are written for OpenOffice.org Calc. Replace semi-colons with commas for Excel.
Confidence interval statistics | |||
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Statistic or Parameter | Symbol | Equations | OpenOffice |
Find the limit for a confidence interval for n ≥ 30 using a normal distribution with p as the area to the left of the limit | =NORMINV(p;μ;σ/SQRT(n)) | ||
Degrees of freedom | df | = n − 1 | =COUNT(data)-1 |
Find a tc value from a confidence level c and sample size n | tc | =TINV(1-c;n-1) | |
Calculate the margin of error E for a mean for any n ≥ 5 using sx. | E | =tc*sx/SQRT(n) | |
Calculate a confidence interval for a population mean μ from the sample mean x and margin of error E for the mean. | x − E ≤ μ ≤ x + E |