chapter 2 stats (descriptive stats)

Box Plot:

graphical representation of a data set, in which one can visually observe potential outliers in the data, if they present.

Chebyshev’s Theorem:

Probability rule for ANY data set.

Empirical Rule

Probability rule for bell-shaped data set.

Frequency (F):

the number of times a value of the data occurs in a data set

Histogram

a graphical representation of a data set, in which one can visually observe the distribution of data.

Interquartile Range (IQR):

is the range of the middle 50% of the data values. It can help to find any potential outliers manually, if they present.

Mean (arithmetic) x^—

the arithmetic average of a data set. It is one of the most important measure of the central tendency of the data.

Median (M)

a number that separates ordered data into halves. It is not affected by potential outliers in the data set.

Mode (m)

: the datum(s) occurs most often in a qualitative data set. It is not affected by potential outliers in the data set and it can be used for quantitative or qualitative data

Outlier:

an observation that is too far away from the center of the data.

Percentile:

a number that divides ordered data into hundredths.

Quartiles

the numbers that separate the data into quarters.

Standard Deviation (s)

a number that is equal to the square root of the variance and it is a very important measure of the data spread (variation) which measures how far data values are from their mean.

Variance s²

The sample variance is equal to the sum of the squares of the deviations divided by the difference of the sample size and one.