1 We use the tdistribution to calculate a confidence interva

1. We use the t-distribution to calculate a confidence interval for the population mean . If we increase the sample size from 10 to 20 the interval would become smaller because of

a. the change in standard error.

b.       both the change in degrees of freedom and the change in standard error

c. none of the other options.

d.       the change in degrees of freedom

Solution

(b) is correct, with higher sample size, the standard error decreases, as well as t-critical value become less extreme.