5.2 BASIC DESCRIPTIVE MEASURES

• LEVELS OF MEASUREMENT

  • Involves the classification of data according to its inherent properties and characteristics
• 4 LEVELS OF MEASUREMENT

  • NOMINAL LEVEL
  • ORDINAL LEVEL
  • INTERVAL LEVEL
  • RATIO LEVEL
• NOMINAL LEVEL

  • Describe a variable with categories that do not have a natural order or ranking and direction.
• ORDINAL LEVEL

  • data can be ordered or ranked, but the differences between the ranks are not meaningful.
• INTERVAL LEVEL

  • Data at this level has meaningful intervals between values, but there is no true zero point.
• RATIO LEVEL

  • This is the highest level of measurement, where data has a true zero point and meaningful ratios.
• Mean - The mean is the average of a set of values, calculated by adding all the numbers together and dividing by the total count of values.
• The mean provides a general idea of the overall value of a data set, but it can be affected by extreme values (outliers).
• The median is the middle value in a data set when the values are arranged in ascending order. If there is an even number of values, the median is the average of the two middle numbers.
• The median is useful for understanding the central tendency of data, especially when there are outliers, as it is not affected by extreme values.
• The mode is the value that appears most frequently in a data set. A data set may have one mode, more than one mode (bimodal or multimodal), or no mode at all.
• The mode is particularly useful for categorical data, where we wish to know which is the most common category.
• The range is the difference between the highest and lowest values in a data set. It provides a simple measure of how spread out the values are.
• Standard deviation measures the average distance of each data point from the mean. It quantifies the amount of variation or dispersion in a set of values.
• standard deviation

  
• The variance for a given set of data is the square of the standard deviation of the data.
• variance