Tableau does not provide calculated field access to the equivalent of the T.DIST() function which provides the student-t distribution. In fact, none of the standard distributions are accessible in this way. However, you don't actually need to use a student-t distribution since your sample size is big enough that a normal distribution is nearly identical. So, you could use an approximation of the normal distribution coded in a calculated field instead. (For a survey of various methods see http://web2.uwindsor.ca/math/hlynka/zogheibhlynka.pdf).
The simplest would be:
.5+(.1*[z Score])*(4.4-[z Score])