yes the fraction of .70 is 7/10
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 answer to this problem is letter d
10x10=100
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Let us analyze the following situation: The number we want to divide by 1/2 is X. We can write:
X/(1/2)=(X/1)/(1/2)=(X*2)/(1*1)= X*2,
which means that the number that is divided with 1/2 is multiplied by 2 (twice the original number).
W<span>hen you divide a number by 1/2, the result is twice the original number . Answer:B</span>