±tsnplus or minus the fraction with numerator t s and denominator the square root of n end-root end-fraction is the number of fields and is the Student’s t-value for the desired confidence. Importance in Material Science
: A transparent grid with equally spaced points is superimposed over a specimen image (micrograph or viewing screen). Points falling within the phase of interest are counted across multiple fields to achieve statistical significance. The Point Counting Procedure astm e56219 pdf
: Measurements must be taken on different fields of view. Repeatedly counting the same micrograph is not permitted by the standard. ±tsnplus or minus the fraction with numerator t