To estimate the number of classmates who do not belong to a major political party, we can use the proportion of students in the sample who do not belong to a major political party as a basis.
Out of the 40 students surveyed, 10 do not belong to a major political party, so the proportion is 10/40 = 0.25.
We can then multiply this proportion by the total number of classmates to estimate the number who do not belong to a major political party:
0.25 * 250 classmates = 62.5 classmates
So about 62 or 63 of the 250 classmates are estimated to not belong to a major political party.