All freshmen at a university are enrolled in 1 of 30 sections of a seminar course. to select a sample of freshmen at this university, a researcher selects 4 sections of the seminar course at random from the 30 sections and all students in the 4 selected sections are included in the

Cluster.

Step-by-step explanation:

In the question To select a sample of freshmen at this university, a researcher selects 4 sections of the seminar course at random from the 30 sections and all students in the 4 selected sections are included in the sample Cluster.

Cluster sampling is type of sampling method in which the researchers divide the population into separate group called clusters. Then a simple random sample is cluster is chosen from the population. And the researcher conducts his analysis on the data from the cluster sample.

Similar activity can be observed in the given case and hence it can be called as sample cluster.

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!