Gina mixed paint to make her favorite shade of purple. She filled up one third of the container with red paint. Then she filled
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Answer:
A sample size of 554 is needed.
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 .
That is z with a pvalue of , so Z = 1.96.
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.
Standard deviation is known to be $12,000
This means that
What sample size do you need to have a margin of error equal to $1000, with 95% confidence?
This is n for which M = 1000. So
Dividing both sides by 1000:
Rounding up:
A sample size of 554 is needed.