Population size N is regarded as effectively infinite if N is at least 20 times sample size (n)

so N/n ≥ 20 => N ≥ 20n

so N should be at least 20n

a) By using Rule of thumb,

Minimum needed value of N to be regarded as effectively infinite for sample of 6 students is 20n i.e 20*6 = 120

University students are more than 120.

b) By using Rule of thumb,

Minimum needed value of N to be regarded as effectively infinite for sample of 58 students is 20n i.e 20*58 = 1,160

University students are more than 1,160.

c) By using Rule of thumb,

Minimum needed value of N to be regarded as effectively infinite for sample of 103 students is 20n o.e 20*103 = 2,060

University students are more than 2,060.