Skip to content

Assumptions for Two Means

You are currently viewing a sample of the Cram Kit. Click here to unlock everything.

These assumptions ensure that our sampling distribution is normal when working with two means. That way, we can use z-scores / t-scores!

#1: Both samples are randomly selected from the population.

#2: Both sample sizes (n1 and n2) is less than or equal to 10% of their respective population sizes.

#3: Both sample sizes (n1 and n2) are greater than or equal to 30, or the populations themselves are normally distributed.

  • Once sample size reaches 30, the Central Limit Theorem ensures that the sampling distribution will be normal.
  • If the underlying population distribution is normal, then our sampling distribution will automatically be normal!

#4: Both samples are independent of each other.

Activate AutoScroll