**PURPOSE**- Computes the t-test values for pairs of points from two average images/volumes resulting from adding two image/volume series.

**SEE ALSO****AS R**[Average image/volume series, optional subset] **EP**[Error Probability] **EP TM**[T test - Each Point]

**USAGE**- .OPERATION: EP TT

- .FIRST AVERAGE FILE: AVE001

[Enter the name of the file containing the average of first image series. This is obtained by using operation 'AS R'.].FIRST VARIANCE FILE: VAR001

[Enter the name of the file containing the variance of first image series. This is obtained by using operation 'AS R'.].NUMBER OF IMAGES AVERAGED: 56

[Enter the number of images added when the first average image was formed.].SECOND AVERAGE FILE: AVE001

[Enter the name of the file containing the average of second image series. This is obtained by using operation 'AS R'.].SECOND VARIANCE FILE: VAR001

[Enter the name of the file containing the variance of second image series. This is obtained by using operation 'AS R'.].NUMBER OF IMAGES AVERAGED: 56

[Enter the number of images added when the second average image was formed.].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 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**- TTEST

**CALLER**- CONF1

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