Answer:
b. 2.333
Step-by-step explanation:
Test if the mean transaction time exceeds 60 seconds.
At the null hypothesis, we test if the mean transaction time is of 60 seconds, that is:
[tex]H_0: \mu = 60[/tex]
At the alternate hypothesis, we test if it exceeds, that is:
[tex]H_1: \mu > 60[/tex]
The test statistic is:
[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, s is the standard deviation of the sample and n is the size of the sample.
60 is tested at the null hypothesis:
This means that [tex]\mu = 60[/tex]
A sample of 16 ATM transactions shows a mean transaction time of 67 seconds with a standard deviation of 12 seconds.
This means that [tex]n = 16, X = 67, s = 12[/tex]
Value of the test statistic:
[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]
[tex]t = \frac{67 - 60}{\frac{12}{\sqrt{16}}}[/tex]
[tex]t = \frac{7}{3}[/tex]
[tex]t = 2.333[/tex]
Thus, the correct answer is given by option b.
