**PURPOSE**- Computes the t-test values for each point in the average image/volume (resulting from adding an image/volume series) versus specified values. This operation tests whether the average image is significantly different from assumed values, for example whether values in the average image differ from zero. Example.

**USAGE**- .OPERATION: EP TM

- .AVERAGE FILE: AVE001

[Enter name of the file containing the average of an image series. This can be obtained from operation 'AS R'.].VARIANCE FILE: VAR001

[Enter name of the file containing the variance of an image series. This can be obtained from operation 'AS R'.].NUMBER OF IMAGES AVERAGED: 56

[Enter the number of images added when the average image was formed.].TESTED POPULATION MEAN: ARF001

[Enter value of population mean.].SIGNIFICANCE IMAGE: SIG001

[Enter the name of the file which will contain the statistical significance of the point-by-point differences.]

**NOTES**

- For an elementary introduction into the theory of
statistical inference, see (e.g.) P. Armitage, "Statistical
Methods in Medical Research", Blackwell Scientific
Publications, p99ff.
- Since the correct normalization of EM images is usually unknown
the results of t-test should be taken with a grain of salt.
- Implemented by: P. Penczek.

**SUBROUTINES**- TTEST1

**CALLER**- CONF1

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