Normal Distribution & Z-scores Flashcards
What is a NORMAL DISTRIBUTION?
the collection of data from a sample that represents the regular and usual behavior or responses from people or items without any treatment or test. Special features like the center, spread, and shape of the data are calculated.
What is a NORMAL CURVE?
the bell-shaped image that is created from the data that is collected from a sample that represents the regular and usual behavior or responses from people or items without any treatment or test. This bell-shaped image has symmetry. It is symmetrical at the mean.
What is the MEAN?
the center value in the collection of data values.
What is STANDARD DEVIATION?
the amount of difference or distance that the collected data values are from the center value.
What is the EMPIRICAL RULE?
a rule in statistics that states the following:
1.) The total percentage under the Normal Curve equals 100%.
2.) About 68% of the total percentage (or probability) exists within one standard deviation of the mean.
3.) About 95% of the total percentage (or probability) exists within two standard deviations of the mean.
4.) About 99.7% of the total percentage (or probability) exists within three standard deviations of the mean.
What is STANDARD NORMAL DISTRIBUTION?
the collection of data from a sample that represents the regular and usual behavior or responses from people or items without any treatment or test. The data center (the mean) is set equal to zero. The data spread (the standard deviation) is set equal to one. The data shape is set to match a bell-shaped curve.
What is a Z-SCORE?
a number that represents the number of standard deviations that a data value in a sample is above or below the center value (the mean).
What is a BELL-SHAPED CURVE?
the curve that is created after plotting data when the mean and median of a data set have the same value.
What is a SKEWED-LEFT CURVE?
the curve that is created after plotting data when the mean of the data set is less than the median of the data set.
What is a SKEWED-RIGHT CURVE?
the curve that is created after plotting data when the mean of the data set is greater than the median of the data set.
