Which of the following statements are true? I. The sampling distribution of ¯ x x¯ has standard deviation σ √ n σn even if the population is not normally distributed. II. The sampling distribution of ¯ x x¯ is normal if the population has a normal distribution. III. When n n is large, the sampling distribution of ¯ x x¯ is approximately normal even if the the population is not normally distributed. I and II I and III II and III I, II, and III None of the above gives the complete set of true responses.

Respuesta :

Complete Question

Which of the following statements are true?

I. The sampling distribution of [tex]\= x[/tex] has standard deviation [tex]\frac{\sigma}{\sqrt{n} }[/tex] even if the population is not normally distributed.

II. The sampling distribution of [tex]\= x[/tex]   is normal if the population has a normal distribution.

III. When  n is large, the sampling distribution of [tex]\= x[/tex]  is approximately normal even if the the population is not normally distributed.

A  I and II

B  I and III

C II and III

D I, II, and III

None of the above gives the complete set of true responses.

Answer:

The correct option is  D

Step-by-step explanation:

Generally the mathematically equation for evaluating the standard deviation of the mean([tex]\= x[/tex]) of samples is  [tex]\frac{\sigma}{\sqrt{n} }[/tex]  hence the the first statement is correct

   Generally the second statement is true, that is the sampling distribution of the mean ([tex]\= x[/tex]) is  normal given that the population distribution is  normal

 Now  according to central limiting theorem given that the sample size is  large the distribution of the mean ([tex]\= x[/tex]) is approximately  normal notwithstanding the distribution of the population