Also, you've got to figure out if you're dealing with a one-sided or a two-sided question, as well as which way the data is going. Meanwhile, two-sided questions ask about two Z-scores, namely the data in between them or outside of them.
Figuring out which direction the data is going in is relatively easy.
For example, a Z-score of 1 represents a value that is one standard deviation greater than the mean, and a Z-score of -1 represents a value that is one standard deviation less than the mean. Oh, by the way, Z-scores are almost always limited to just two decimal points.
As you will see, this is because the resulting percentages are very precise.
A positive Z-score refers to a standard deviation that is to the right of the mean, meaning that it is greater than the mean.
On the other hand, a negative Z-score refers to a standard deviation that is to the left of the mean, meaning that it is less than the mean.
Plus, get practice tests, quizzes, and personalized coaching to help you succeed.
Try it risk-free In this lesson, we will put the normal distribution to work by solving a few practice problems that help us to really master all that the distribution, as well as Z-Scores, have to offer. If you've been working with normal distributions for long, you've probably figured out that they are pretty useful things.
Solution: The probability of score falling between 75 and 95 can be found after finding the respective z-scores.
established that independent random variables tend to be normally distributed.