Probability and Statistics
Approximately 95% of all the data in a normal distribution lie within ___ standard deviations of the mean.
2
Approximately 99.7% of all data in a normal distribution lie within ___ standard deviations of the mean.
3
What is the shape of a normal distribution?
Bell shaped
Normal curves are _________ mathematical models that describe a wide variety of experiments and natural occurrences and have special properties that allow the assignment of probabilities to outcomes.
Bell shaped
Normal curve never touches the ____.
Horizontal axis
Empirical rule
In normally distributed data, about 68% of the data is within one standard deviation of the mean, 95% of the data is within two standard deviations of the mean, and 99.7% of the data is within three standard deviations of the mean. (68-95-99.7 rule)
Approximately 68% of all the data in a normal distribution lie within ___ standard deviation of the mean.
1
The area under a normal curve is ____.
1
Normal curve
the curve representing a normal distribution
The mean, median, and mode all occur at the ____ of a normal distribution.
Peak
What letter represents the mean of a normal distribution?
The lowercase Greek letter, mu. Half the data are above it, half are below it.
What letter represents the standard deviation of a normal distribution?
The lowercase Greek letter, sigma.
What percent of the data in a normal Distribution are more than 3 standard deviations away from the mean?
in a normal distribution, about 0.3% of the data are more than 3 standard deviations away from the mean. The corresponding areas on the graph are so small (each 0.15% of the distribution) you can hardly see it.
Normal distribution
bell-shaped distribution, centered on the mean