Answer: Stratified Random Sampling
Step-by-step explanation: Got it right
Average (mean) = (sum of all the data) / (# of data)
sum of all the data = (average)(# of data)
Thus for 100 students with an average of 93,
sum of all data = (93)(100) = 9300
and for 300 students with an average of 75,
sum of all data = (75)(300) = 22500
Therefore you would expect the overall average to be
(9300 + 22500) / (100 + 300) = 79.5 %
Now if there are x # of advanced students and y # of regular students, then
x + y = 90 (total # of students) and 93x + 75y = 87(x + y) (overall average)
The second equation can be simplified to x - 2y = 0
Subtracting the two equations yields
x = 60 and y = 90
Therefore you would need 60 advanced and 30 regular students.
The first one would be the right one!
you just take all the y one side and the numbers on one side
so 8y+4= 6+3y
now 8y-3y= 6-4
therefore 5y = 2
!!
Answer:
ok then
Step-by-step explanation:
gooood............