Answer:
609
Step-by-step explanation:
Standard deviation =
= $30
Margin of error = E = $2
Confidence level = 90%
Since the distribution is said to be normal, we will use z scores to solve this problem.
The z score for 90% confidence level = z = 1.645
Sample size= n = ?
The formula to calculate the margin of error is:

Using the values in above equation, we get:

This means, the minimum number of observations required is 609
A hypothesis is only tentative: to make sure it's valid, you have to test it.
Answer:
16π or 50.24
Step-by-step explanation:
Area of a circle is πr^2
π*4^2
16π
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