Normal distribution = Follows the 95-68-99 rule

The numbers represents the proportion of the population that fits under the standard deviations. For example, If you start to check on the most average of the population, and you see that 68% of the whole population fits around that category, and then you check on a broader category, and found out that 95% of the population fits that category, and then 99.7% fits the even broader category, this is a typical example of a normal distribution. Here's a pretty good example of it.

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Sample proportion = The proportion of the sample that successes, or meets certain conditions.

For example, you have a sample population of 50 people. You want to test how many of them have diabetes. Your test results indicates that 10 of them have diabetes. The sample proportion will be 10/50=0.2