Answer:
The margin of error is of 0.73 oz.
The 99% confidence interval for the true mean weight of the boxes is between 14.57 oz and 16.03 oz. This means that we are 99% sure that the true mean weight of all boxed produced by the Packaging Company is between these two values, and that the specified weight is in this interval.
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:
![\alpha = \frac{1 - 0.99}{2} = 0.005](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%5Cfrac%7B1%20-%200.99%7D%7B2%7D%20%3D%200.005)
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 = 2.575.
Now, find the margin of error M as such
![M = z\frac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
In which
is the standard deviation of the population and n is the size of the sample.
![M = 2.575\frac{1.7}{\sqrt{36}} = 0.73](https://tex.z-dn.net/?f=M%20%3D%202.575%5Cfrac%7B1.7%7D%7B%5Csqrt%7B36%7D%7D%20%3D%200.73)
The margin of error is of 0.73 oz.
The lower end of the interval is the sample mean subtracted by M. So it is 15.3 - 0.73 = 14.57 oz.
The upper end of the interval is the sample mean added to M. So it is 15.3 + 0.73 = 16.03 oz.
The 99% confidence interval for the true mean weight of the boxes is between 14.57 oz and 16.03 oz. This means that we are 99% sure that the true mean weight of all boxed produced by the Packaging Company is between these two values, and that the specified weight is in this interval.