Question

How to calculate p value from bland altmann plot?

Answer 1

his procedure is available in both the Analyse-it Standard and the Analyse-it Method Evaluation edition

Altman bland test determines the agreement between two variables.

The requirements of the test are:

Two variables measured on a continuous scale.Replicates can be observed for each variable, though the two variables need not have the same number of replicates.Each cases must have the same number of replicates, otherwise the entire case will be listwise deleted.Arranging the datasetUsing the testUnderstanding and configuring the bias plotDetermining and plotting biasDetermining and plotting limits of agreementExamining RepeatabilityReferences to further readingArranging the dataset

Data in existing Excel worksheets can be used and should be arranged in the List dataset layout. The dataset must contain at least two continuous scale variables. If replicates are observed then a List dataset with grouped variables layout should be used to arrange the replicates for each variable.

When entering new data we recommend using New Dataset to create a new 2 variablesdataset ready for data entry.

Using the test

To start the test:

Excel 2007: 
Select any cell in the range containing the dataset to analyse, then click Agreement on the Analyse-it tab, then click Bland-Altman.  Excel 97, 2000, 2002 & 2003: 
Select any cell in the range containing the dataset to analyse, then click Analyse on the Analyse-it toolbar, click Agreement then clickBland-Altman.Click Variable X and Variable Y and select the variables.Click OK to run the test.

The report shows the number of cases analysed, and, if applicable, how many cases were excluded due to missing values. The number of replicates and repeatability SD/CV (depending on the Plot option, see below) of each variable is shown.

The scatter plot (see below) shows the observations of X plotted against Y. The Use replicatesoption determines how replicates for each variable, if available, are plotted.