複選題

18. A researcher compares the average amount of daily screen time between teenagers and adults. Which of the following statements are correct?
(A) The null hypothesis would state that there is a big difference in screen time between the two groups.
(B) A very significant t-test result (p < 0.01) would suggest rejecting the null hypothesis.
(C) A smaller confidence level would result in a wider confidence interval.
(D) An F-test must be performed before the t-test to validate equal variances.
(E) A high F value suggests the two groups have the very similar daily screen time with a lower Q value.