5Step-by-step explanation:
Answer:
(a)
and 
(b) The sample variance is
and the sample standard deviation is 
Step-by-step explanation:
(a)
The sum of these 17 sample observations is

and the sum of their squares is

(b)
The sample variance, denoted by
, is given by

where 
Applying the above formula we get that


The sample standard deviation, denoted by <em>s</em>, is the (positive) square root of the variance:

Applying the above formula we get that

Answer:
Andrew will do 7 1/2 + 7 1/2 which equals 15
Step-by-step explanation:
Hope it helps
Im not completely sure that its right...
My teacher taught me a simple equation for these types of problems:
(percent of solution × amount of solution) + (percent of solution × amount of solution) = (percent of solution × total amount of solution)
in simple terms: %amount + %amount = %total amount
We know don't know how much gallons of 60% solution we need so it will be represented as x. We dont know the total amount either so it would have to be both solutions added together so 50 + x. Now lets solve:
(0.60)(x) + (0.24)(50) = (0.50)(50 + x) simplify/ distribute
0.6x + 12 = 25 +0.5x get all xs on one side and numbers on other
0.1x + 12 = 25
0.1x = 13 divide both sides by 0.1 to find x
x = 130
You need 130 gallons of 60% solution.
If there is 23 classrooms and each has 10 then you would have to times 23 by 10 - 23x10=230