02_Data_Treatment-page14

# 02_Data_Treatment-page14 - Risk of false rejection....

This preview shows page 1. Sign up to view the full content.

Assumes that you have some idea as to what the standard deviation should be or can calculate it. | suspect - mean| S If M > 4 then you can reject the point. This is simply a crude t test. It is only useful for discarding obviously ‘bad’ data. M = Use ratio ' 10 for 3 - 7 data points. x n - x n-1 x 2 - x 1 x n - x 1 x n - x 1 ' 10 = or Two versions based on if its the lowest or highest value that is being tested. to test high value to test low value For 8-10 points, use ' 11 x n - x n-1 x 2 - x 1 x n - x 2 x n-1 - x 1 For 11-13 points, use ' 21 x n - x n-2 x 3 - x 1 x n - x 2 x n-1 - x 1 For 14-25 points, use ' 22 x n -x n-2 x 3 - x 1 x n -x 3 x n-2 - x 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Risk of false rejection. Statistic n 0.5% 1% 5% 10% ' 10 3 .994 .988 .941 .886 4 .926 .889 .765 .679 5 .821 .780 .642 .557 6 .740 .698 .560 .482 7 .680 .637 .507 .434 ' 11 8 .725 .683 9 .677 .635 10 .639 .679 ' 21 11 .713 .642 12 .675 .615 13 .649 ' 22 14 .674 15 .647 This approach requires calculation of the mean and standard deviation 1. Rank points 2. Pick suspect points 3. Calculate mean and standard deviation using all points. 4. Calculate T. T = |mean - suspect| / s x 5. Look up T on table. If T > table value then reject it....
View Full Document

## This note was uploaded on 01/07/2012 for the course CHEM 290 taught by Professor Harvey during the Fall '08 term at SUNY Stony Brook.

Ask a homework question - tutors are online