A sports club needs to raise at least $500 by selling chocolate bars for $2.50 each. Sebastian wants to know how many chocolate
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Answer:
The 90% confidence interval using Student's t-distribution is (9.22, 11.61).
Step-by-step explanation:
Since we know the sample is not big enough to use a z-distribution, we use student's t-distribution instead.
The formula to calculate the confidence interval is given by:
Where:
is the sample's mean,
is t-score with n-1 degrees of freedom,
is the standard error,
is the sample's size.
This part of the equation is called margin of error:
We know that:
degrees of freedom
Replacing in the formula with the corresponding values we obtain the confidence interval: