Given:
The expression is
To find:
The equivalent expression.
Solution:
Distributive property of multiplication over addition is
Where, a, b and c are real numbers.
We have,
Using distributive property, we get
Therefore, the expression is equivalent to the given expression.
Answer:
We need a sample size of at least 1161.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error for the interval is:
For this problem, we have that:
90% confidence level
So , z is the value of Z that has a pvalue of
, so
.
How large a sample should she take?
We need a sample size of at least n.
n is found when
So
Rounding up
We need a sample size of at least 1161.