Question

One characteristic measured about high schools is the percent ree lunch, which is the percentage of the student body that is eligible for free and reduced-price lunches. The top 100schools, how many would be selected from the stratum with a percent-free-lunch value of schools, grouped according to their percent free lunch, is as follows. If stratified random sampling with proportional allocation is used to select a sample of 25 high 20s x <30? Percent free Number of top 100 (Round up to the nearest integer.) lunch (x) ranked high schools 45 21 13 10 х<20 20s x s 30 40s x 13

Answer 1

Total number of schools = 100

Total number of schools in the sample = 25

So, number of schools selected from the stratum with a percent-free-lunch value of $20\leq x<30$

= $\frac{13}{100}\times 25=3.25\approx 3$

i.e. 3 schools