Answer:
D. +3.82
Step-by-step explanation:
The null hypothesis is:
[tex]H_{0} = 8500[/tex]
The alternate hypotesis is:
[tex]H_{1} > 8500[/tex]
Our test statistic is:
[tex]t = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the expected mean(null hypothesis), [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
In this problem:
[tex]X = 8745, \mu = 8500, \sigma = 1200, n = 350[/tex]
So
[tex]t = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]t = \frac{8745 - 8500}{\frac{1200}{\sqrt{350}}}[/tex]
[tex]t = 3.82[/tex]
