Comparison of summarized data, frequency data, and raw data

Data that summarize all observations in a category are called summarized data. The summary could be the sum of the observations, the number of occurrences, their mean value, and so on. When the summary is the number of occurrences, this is known as frequency data. This is in contrast to raw data, where each row in the worksheet represents an individual observation.

  • To obtain frequency data, choose Stat > Tables > Tally Individual Variables. Make sure that you store the results in the worksheet.
  • To obtain summarized data other than counts of occurrences, choose Stat > Basic Statistics > Store Descriptive Statistics.

Raw Data

When a factory has a production error, the manager records which factory it was in the worksheet.

Frequency Data

The manager summarizes the number of occurrences in this worksheet. The first row shows that factory A had 106 errors.
C1-T C2
Factory Production Errors
A 106
B 127
C 186
D 155

Summarized Data

Suppose the manager wanted the average number of errors, not the total. They record the number of productions errors per week in each factory for a year. The worksheet has a column with the factory name and a column with the number of errors that week. But because the manager recorded data for an entire year, his worksheet has 208 rows (52 weeks x 4 factories). The manager can use summarized data to determine the average number of errors per week in each factory.
C1-T C2
Factory Average production errors per week
A 2.1
B 2.4
C 3.6
D 3.0