Answer:
[tex]46500 \pm 1.74\frac{10200}{\sqrt{18}}[/tex]
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 18 - 1 = 17
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 17 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 1.74
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 1.74\frac{10200}{\sqrt{18}}[/tex]
Confidence interval:
Sample mean plus/minus margin of error. So
[tex]46500 \pm 1.74\frac{10200}{\sqrt{18}}[/tex]