Use the simple statistics calculator to calculate the standard error of the mean.
The Standard Error ("Std Err" or "SE"), is an indication of the reliability of the mean. A small SE is an indication that the sample mean is a more accurate reflection of the actual population mean. A larger sample size will normally result in a smaller SE (while SD is not directly affected by sample size).
STANDARD ERROR CALCULATION
How do you calculate the standard error?
- Step 1: Calculate the mean (Total of all samples divided by the number of samples).
- Step 2: Calculate each measurement's deviation from the mean (Mean minus the individual measurement).
- Step 3: Square each deviation from mean. Squared negatives become positive.
- Step 4: Sum the squared deviations (Add up the numbers from step 3).
- Step 5: Divide that sum from step 4 by one less than the sample size (n-1, that is, the number of measurements minus one)
- Step 6: Take the square root of the number in step 5. That gives you the "standard deviation (S.D.)."
- Step 7: Divide the standard deviation by the square root of the sample size (n). That gives you the "standard error".
- Step 8: Subtract the standard error from the mean and record that number. Then add the "SE" to the mean and record that number. You have plotted mean ± 1 standard error (S. E.), the distance from 1 standard error below the mean to 1 standard error above the mean
Formula:
SEX = s / √n
where,s - sample standard deviation
n - size of the sample