A study will investigate the effectiveness of a new textbook. The samples (

In= 30 and n= 35) included in the study are taught by two professors. Which

of the following are possible limitations of the study? Select all that apply.

A. the sample size too small

B. The teachers may differ in number of years teaching

C. The teachers may differ in expenrince in using a virtual applets

D. The teacher may differ in their approach of using the applets