3. When a random variable X follows X ~ N(u, 2) , which of the following is correct as a standardized expression? 1 1/x 2 ( X - H ) / o 3 (X - 0) / H 4 ( X - H ) 4. If a sample of 100 people was selected to find out whether satisfaction about two subjects differed according to gender, which statistic would be the most appropriate in this case? Hint: think of the nature of the studied variable first. 1 t 2 x2 3 Z 4 F