Question

1. For a sample with a mean of 150 and standard deviation 25, what is the lower limit of the 95% confidence interval?

A> 91.75
B> 101
C> 108.75
D> None of the above

Answer 1

Marginal error can be calculated using =CONFIDENCE.NORM(0.05,25,1) excel formula which yields 48.9991. thus The lower limit of the 95% confidence interval is given by $150-48.99909961=101.0009004$

Thus, the correct answer is option B.