Q) Albert owns a farm, he wants to check the overall health of his animals he chooses cows, horses and rabbits.
He decides to take a sample size of 30.
Animal: Cows Horses Rabbits
Total: 40 60 50
Sample: 8 12 10
A) how I worked it out:
40/5=8 60/5=12 50/5=10 Thats how many animals he checks
To check you've done it correctly just add 8+12+10=30 it equals 30 which is your sample size.
Hope that helped you :):)
I was doing a past paper the other day and it had a stratified sampling question in but not like the one on the other card i did, so i thought i'd tell you how to complete it incase you come across one like it and don't know how to work it out.
Q) A sample of runner was taken from a group, stratified by age to complete a survey. Complete the table;
Age group Frequency Number in sample
18< r<30 240 12 <------------(first one done for you)
30<r<40 450 23
40<r<50 170 9
50<r<70 80 4
What i did; 240/12=20 (20 is the sample number we need to make it into a fraction- 1/20)
then you do (450/20)x1 = 23 and so on... (170/20)x1=9...
I didn't get how to do this question at first, but i worked it out after so i hope it helped you :)