Notice that the distribution is symmetric when p = 0.5. .

Set p to 0.8. Is the distribution still symmetric, or is its tail longer in one direction or the other? If the tail is longer on the right side, it is called positive skew; if it is longer to the left, it is called negative skew. Now set p to 0.2 and note the results.

No consider how the value of p affects how spread out the distribution is. Using the standard deviation as the measure of spread, examine the spread for p= 0.1, 0.3, 0.5, 0.7, and 0.9. Which value has the largest spread? Which value(s) have the smallest spread?

How does N affect the mean of the binomial distribution? Setting p back to 0.5, find the mean for N = 10 and N = 20. It makes sense that the mean number of successes is greater when you have more trials.

You learned earlier using N = 10 that the distribution is symmetric only when p = 0.5; otherwise it is skewed. How does N affect the skew? Compare the skew for N = 10, p = 0.8 with the skew for N = 50, p = 0.8. Both distributions are negatively skewed, but notice which one only has a very small skew.