Answer:
a. (1.811, 1.929)
Step-by-step explanation:
We have to find find M as such
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
In which, z is Z(a/2), [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample. So
[tex]M = 2.58*\frac{0.125}{\sqrt{30}} = 0.059[/tex]
The lower end of the interval is the mean subtracted by M. So it is 1.87 - 0.059 = 1.811.
The upper end of the interval is the mean added to M. So it is 1.87 + 0.059 = 1.929
So the correct answer is:
a. (1.811, 1.929)
