Statistics - Terms and Definitions

Question 1

Measures of Central Tendency

Answer 1

The purposes of a measure of central tendency is to determine the “center” of a distribution of data values or possibly the “most typical” data value. Mean, median, and mode are measures of central tendency.

Question 2

Mean (arithmetic)

Answer 2

Calculated by adding together all the observations and dividing by the number of observations.

Question 3

Median

Answer 3

The middle observation of a data set of ordered observations if the number of observations is odd. It is the average of the middle pair is the number of observations is even.

Question 4

Mode

Answer 4

The number that appears the most often within the data set.

Question 5

Measures of dispersion

Answer 5

the purpose of measures of dispersion is to develop an understanding of the dispersion, or spread, of a data set.

Question 6

Dispersion

Answer 6

The degree to which numerical data tend to spread around an average value. Variance, standard deviation, and coefficient of variation are ways to measure dispersion.

Question 7

Variance

Answer 7

The variance is equal to the sum of the squared deviations between each observation and the mean value

Question 8

Standard Deviation

Answer 8

The square root of the variance.

Question 9

Coefficient of Variation

Answer 9

The ratio of the standard deviation to the mean and measure of relative dispersion

Question 10

Measures of Relative Position

Answer 10

These describe the relative position of an observation in a data set.

Question 11

Percentiles (Decile and Quartile)

Answer 11

Gives valuable information about the rank of an observation, and if a set of data is arranged in order of magnitude, the middle value which divides the data set into two equal parts is the median. By extending this idea, we can think of those values which divide the data set into four equal parts (quartiles). Similarly, the values which divide the data into ten equal parts are called deciles.