Statistics Definitions



Statistics Definitions

Survey- (book, )

Observation-(book, )

Controlled Experiment- (book, )

Grouped Data- (book)… Cumulative Frequency Chart is used because there is too much data to list all individually

Range- (book, )

Absolute Deviation- of an element of a data set is the absolute difference between that element and a given point. Typically the point from which the deviation is measured is a measure of central tendency, most often the median or sometimes the mean of the data set.

Di = | xi − m(X) |

Variance- the variance is a measure of the amount of variation within the values of that variable, taking account of all possible values and their probabilities or weightings

Standard Deviation- It shows how much variation there is from the "average" (mean) (or expected/budgeted value). It helps detect tampering of data. A low standard deviation indicates that the data points tend to be very close to the mean, whereas high standard deviation indicates that the data are spread out over a large range of values.

In addition to expressing the variability of a population, standard deviation is commonly used to measure confidence in statistical conclusions. For example, the margin of error in polling data is determined by calculating the expected standard deviation in the results if the same poll were to be conducted multiple times. The reported margin of error is typically about twice the standard deviation – the radius of a 95% confidence interval. In science, researchers commonly report the standard deviation of experimental data, and only effects that fall far outside the range of standard deviation are considered statistically significant—normal random error or variation in the measurements is in this way distinguished from causal variation. Standard deviation is also important in finance, where the standard deviation on the rate of return on an investment is a measure of the volatility of the investment.

Sample Population vs. Population- (book, )

Normal Distribution- (book, )

Z- score-(book, )

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