Answer:
We need to sample at least 1069 parents.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
How many parents do you have to sample?
We need to sample at least n parents.
n is found when 
. So
Rounding up
We need to sample at least 1069 parents.
The smallest common denominator is 30 in so
<span>9/10=27/30 and 5/6=25/30 are your answers ; ]</span>
I always start by moving the last term to the other side
To complete the square you take term 'b' , divide it by 2 then square it
= 25
We have to add 25 to what we have and what you do to one side you have to do to the other
Now we factor what is on the left side of the equation
The last step is to move our right side of the equation back over
- which is your answer :)))
