1.3 Frequency, Frequency Tables, and Levels of Measurement

Levels of Measurement

Data can be classified into four levels of measurement. Correct statistical procedures depend on a researcher being familiar with levels of measurement. Not every statistical operation can be used with every set of data.

From Lowest to Highest: Nominal, Ordinal, Interval, Ratio (NOIR)

Frequency is the number of times a value of the data occurs. It’s the count of that data value.

Relative Frequency i the ratio (fraction or proportion) of the frequency of a value to the total number of data values in the data set (This is often the sample size or the total number of outcomes).

Cumulative relative frequency is the accumulation of the previous relative frequencies. To find the cumulative relative frequencies, add all the previous relative frequencies to the relative frequency for the current row. In other words, accumulate (add up) relative frequencies of all rows from the top to the current row for its relative frequency. For the last row, the cumulative relative frequency will equal 1 or 100%.

Think about how relative cumulative frequency is calculated using relative frequencies from prior classes. If we apply the same approach to frequencies, we’ll have ourselves the cumulative frequencies! The cumulative frequency for the last row (class) will be the same as the sample size (size of the data set).