Answer:
For the first group, with 19 degrees of freedom, the critical value is t=2.093.
For the second group, with 21 degrees of freedom, the critical value is t=2.080.
Step-by-step explanation:
The critical value of the t-statistic depends on the significance level and the degrees of freedom of the sample.
For a significance level of 0.05, for a two-tailed test, there is an upper 2.5% and a lower 2.5%.
For the first group, with 19 degrees of freedom, the critical value is t=2.093.
For the second group, with 21 degrees of freedom, the critical value is t=2.080.
