Econ Stats Mod 2

A frequency table

a grouping of qualitative data into mutually exclusive (each observation in only one class) and collectively exhaustive (there is a class for each value) classes showing the number of observations in each class.

A relative frequency table

shows the fraction of the number of frequencies in each class.

A bar chart

a graphic representation of a frequency table. Bars are SEPERATE

A pie chart

shows the frequency of each distinct class as a proportion of the total number of observations.

A frequency distribution

a grouping of raw data into mutually exclusive and collectively exhaustive classes showing the number of observations in each class.

The steps in constructing a frequency distribution are

1. Decide on the number of classes.

2. 2.Determine the class interval.

3. Set the individual class limits.

4. Tally the observations into classes.

5. Count the number of observations in each class.

The class frequency

is the number of observations in each class.

The class interval

is the difference between the limits of two consecutive classes.

The class midpoint

is halfway between the limits of consecutive classes.

A relative frequency distribution

shows the percent of observations in each class. (class frequency/total # of observations)

A histogram

portrays the frequencies in the form of a rectangle or bar for each class. The height of the rectangles is proportional to the class frequencies. Bars are ADJACENT

A frequency polygon

consists of line segments connecting the points formed by the intersection of the class midpoint and the class frequency.

A graph of a cumulative frequency distribution

shows the number of observations less than a given value.

A graph of a cumulative relative frequency distribution

shows the percent of observations less than a given value.

Qualitative Data

data that can be categorized based on traits or qualities, rather than numerical values. It often involves non-numerical variables such as names, labels, or attributes. Displayed in frequency tables, bar/pie chart

Quantitative Data

data that is numerical values. Displayed in frequency distribution, frequency polygon, histogram

Formula for class number?

2^k>n, where k= # of classes & n= # of values in data set.

Formula for class interval?

I= (max-min) / k , where k=# of classes

Excel formula for Relative Distribution

% of Grand Total

Excel Formula for Cumulative Frequency

Running total in

Relative Cumulative Frequency Distribution

% Running Total In