Mathematics: You measure 34 textbooks weights, and find they have a mean weight of 69 ounces. Assume the population standard deviation is 8.2 ounces. Based on this, construct a 95% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places

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You measure 34 textbooks weights, and find they

kdawg203

22.07.2021

The 95% confidence interval for the true population mean textbook weight is between 66.24 and 71.76 ounces.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.95}{2} = 0.025$

Now, we have to find z in the Z-table as such z has a p-value of $1 - \alpha$ .

That is z with a pvalue of 1 - 0.025 = 0.975 , so Z = 1.96.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

$M = 1.96\frac{8.2}{\sqrt{34}} = 2.76$

The lower end of the interval is the sample mean subtracted by M. So it is 69 - 2.76 = 66.24 ounces

The upper end of the interval is the sample mean added to M. So it is 69 + 2.76 = 71.76 ounces.

The 95% confidence interval for the true population mean textbook weight is between 66.24 and 71.76 ounces.

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