Answer:
25 Degrees of Freedom
Explanation:
Significance of difference between two population means (based on sample means) is done with formula : √ [ (Σx1^2 + Σx2^2 / N1 + N2 - 2) (1/N1 +1/N2) ]
with degrees of freedom = N1 + N2 - 2
= 14 + 13 - 2
= 25