Which of the following statements correctly compares the tst

Which of the following statements correctly compares the t-statistic to the z-score when creating a
confidence interval?

A. The value of z relates to a normal distribution, while the value of t relates to a Poisson distribution.
B. Use t when the sample size is small, and the resulting confidence interval will be narrower.
C. You can use t all the time, but for n 30 there is no need, because the results are almost identical if you use t or z.
D. Using t is easier because you do not have to worry about the degrees of freedom, as you do with z.

Solution

The option C is correct because we can use t all the time, but for n 30 there is no need, because the results are almost identical if you use t or z.

As sample size increases the value tends to normally distributed. So, if we use t for large sample size it is equal to z-value.