stats test 1 guide

Continuous Variable

A variable that can take on any value within a given range

Discrete Variable

A variable that can only take on specific, separate values, often whole numbers.

Flawed Question

A survey question with categories that are not exhaustive, meaning they don't include all possible responses

Relative Frequency

The proportion of observations that fall into a specific category or class. It is calculated by dividing the frequency of a category by the total number of observations.

Class Interval

: The range of values within each class of a frequency distribution. It is determined by the difference between consecutive lower or upper class limits

Class Limits

The boundaries for each class in a frequency distribution.

Weighted Mean

An average calculated by multiplying each value by a weight, which reflects its importance or frequency, and then summing the results and dividing by the sum of the weights.

Median

The middle value in a dataset that has been ordered from least to greatest. If there is an even number of values, the median is the average of the two middle values.

Arithmetic Mean Disadvantage

he mean can be heavily influenced, or biased, by one or two extremely small or large values, which may not be representative of the data as a whole.

Variance (for a population):

A measure of the spread of a set of data points around their mean. It is the average of the squared differences from the mean.

Standard Deviation

The square root of the variance. A smaller standard deviation indicates that the data points are clustered closely around the mean, meaning they are less spread out and more predictable.

Chebyshev’s Theorem

A theorem that provides a minimum percentage of observations that must lie within a specified number of standard deviations from the mean for any data distribution.

Empirical Rule

A rule that applies specifically to a bell-shaped, symmetrical, normal distribution. It states that approximately 95% of the data will fall within two standard deviations of the mean.

Geometric Mean

A type of average used for data sets that involve rates of change or are multiplied together, such as calculating the average growth rate.