Continuous Sampling

On the Stats tab, in the Assay Quality Control group: Click Continuous Sampling to check sample data distribution for continuous data.

When you run the continuous sampling function, a Chi² goodness of fit test is performed at the chosen significance level and the result is displayed. Depending on the degree of conformity between the sample data and the selected distribution, the fit will either be accepted or rejected. A message will appear stating the case.

You can also evaluate the test by comparing the calculated Chi² value with the critical value. The distribution will be rejected if Chi² is greater than the critical value. Insufficient sample data is a common reason why the fit may be rejected.

When the message “Degrees of Freedom < 1” appears, you will need to increase the number of bins before proceeding.

Source

File

On the Input Data tab of the Continuous Sampling form, select a file type and then double-click (or click on the Select icon) to select the name of the file containing your data. You can optionally apply a filter to select a subset of the data in the file.

Field

Double-click (or click on the List icon) to select the Input field.

Numeric Exceptions

(Optionally) Use the Numeric Exceptions group to control the way that non-numeric values are handled. Non-numeric values include characters, blanks, and values preceded by a less than sign (<).

Parameters

Min and Max values

Enter the minimum and maximum values to be included in the analysis. One or both of these inputs may be disabled, depending on the distribution you have selected to test.

Number of bins

Enter the number of groups or subdivisions of data.

Distribution

Choose the distribution to test for Continuous sampling:

NONE - Does not display an idealised distribution.
UNIFORM - The distribution shows no central tendency; any value is as likely to occur as another.
NORMAL - Distribution gives a bell shaped distribution curve caused by the symmetrical clustering of values around a central mean.
LOG NORMAL - Displays data values transformed according to the relationship x = lnx, and the distribution of z values is displayed against the normal distribution curve.
EXPONENTIAL - Distribution shows the frequency of values rapidly declining from a peak to a long tail or rising from a base level with increasing steepness.

Significance level

Enter the Significance level at which a Chi² goodness of fit test is performed. The significance level is 100% – Confidence Level% (i.e.: 100% – 95% = 5%).

Display

Input Colour

Double-click on the Colour icon to select a colour for the Input field.

Distribution Colour

Double-click on the Colour icon to select a colour for the line of distribution.

Cumulative display

Select this option to display a cumulative graph of values.

Display mean, std dev

Select this option to display Mean and Standard Deviation as vertical lines. Double-click on the Band colour icon to select a colour for the bands between the lines.

OK

When you have set Input options and customised the Chart and the Axes of the graph, click the OK button to generate the graph.

Forms

Click the Forms button to select and open a saved form set, or if a form set has been loaded, save the current form set.