Linda is buying boxes of ice cream sandwiches for her class party. She has to decide how many boxes she should purchase. A formu
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Answer:
And the 95% confidence interval would be givne by (65.89; 67.11)
Step-by-step explanation:
For this case we have a 99% confidence interval for the true mean hegiht givne by:
And we can begin finding the mean with this formula:
Now we can estimate the margin of error:
The sample size for this case is then the degrees of freedom are given by:
And then we can find a critical value for a 99% of confidence and 143 degrees of freedom using a significance level of 0.01 and we got:
Then the standard error is given by:
Now we can find the other critical value for 95% of confidence and we got:
And the new confidence interval would be given by:
And the 95% confidence interval would be givne by (65.89; 67.11)