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Home / Assignment Help / A math teacher wants to find out the average number of hours his students spend working on their math homework for his class each week. Which group would best represent a sample of the population? the first 30 students who enter the school building one morning 30 students selected from the lunchroom 30 students selected from his class rosters 30 students who stay after school for football practice

# A math teacher wants to find out the average number of hours his students spend working on their math homework for his class each week. Which group would best represent a sample of the population? the first 30 students who enter the school building one morning 30 students selected from the lunchroom 30 students selected from his class rosters 30 students who stay after school for football practice

You need to determine the number of ways in which 30 competitors from 50 can qualify. First, you have to realize that the order is irrelevant, that is: it is the same competitor_1, competitor _2, competitor _3 than competitor_3, competitor_2, competitor_1, or any combination of those three competitors.

So, the number of ways is which 30 competitors from 50 can qualify is given by the formula of combinations, which is:

C (m,n) = m! / (n! * (m -n)! )

=> C (50,30) = 50! / (30! (50 – 30)! ) = (50!) / [30! (50 – 30)!] = 50! / [30! 20!] =

= 47,129,212,243,960 different ways the qualifiying round of 30 competitors can be selected from the 50 competitors.