-10/8 and + 15/8. Those should work.
Answer:
Step-by-step explanation:
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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.