The tutor covers the tdist() function, which seems to work the same on Excel and LibreOffice Calc.

The tdist() function is in the statistics category of functions. Its entry scheme is

=tdist(t-value, degrees_of_freedom, number_of_tails)

Perhaps surprisingly, the t-value itself must be positive. (For a negative value, you just use the corresponding positive one and the idea of symmetry.) The number_of_tails parameter is either 1 or 2.

The function returns the value in the tail, rather than between the center and the input. For instance,

=tdist(2.042,30,2)

yields 0.05: 0.025 from each tail.

Example: Give the probability that, with df=20, a t statistic lies between -0.65 and 0.11.

Solution:

1. On the upper side, the probability will be =0.5-tdist(0.11,20,1). This yields 0.0432.
2. On the lower side, the probability will be =0.5-tdist(6.5,20,1).
   This yields 0.2385.
3. The total probability is the sum of the two, which is 0.0432+0.2385=0.2817
4. Apparently, there is 28.2% probability that a t-statistic with df=20 will land between -0.65 and 0.11.

Source:

Harnett, Donald L. and James L. Murphy. Statistical Analysis for Business and Economics. Don Mills: Addison-Wesley, 1986.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.