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### Course: AP®︎/College Statistics>Unit 9

Lesson 5: Sampling distributions for differences in sample proportions

# Sampling distribution of the difference in sample proportions: Probability example

We can use the mean and standard deviation and normal shape to calculate probability in a sampling distribution of the difference in sample proportions. Created by Sal Khan.

## Want to join the conversation?

• Why did we use a normal approximation in the second example if n was 400 with the combined cars and p was .02 with the combined proportions? Wouldn't n * p = 8 and not be greater than or equal to 10?
(1 vote)
• I may be wrong, but since both distributions are approximately normal, doesn't that mean we can assume that the distribution of their differences is normal as well?