4.2 Describing your data

We explore our data partly to describe our data and partly to check our data before performing inferential statistics. jamovi puts all our descriptive statistics into one useful analysis under the Analyses tab within the Exploration menu called Descriptives.

Describing nominal or ordinal data

Nominal and ordinal data is described mainly using frequencies. Choose your categorical variable(s) and move it to the Variables box and then select the option Frequency tables. Note that it tells you it’s best for nominal and ordinal data with the two icons!

I recommend you watch this video by Alexander Swan on how to describe categorical data in jamovi.

Describing continuous data

Continuous data is described using a variety of measures of central tendency, dispersion, and more. Choose your continuous variable(s) in the list of variables on the left side and move it to the Variables box.

I recommend you watch this video by Alexander Swan on how to describe continuous data in jamovi.

In the Descriptives analysis (these are under the Statistics drop-down menu, there are a ton of possible options!

  1. Sample size: you can ask for the sample size (N) and number of missing values (Missing)
  2. Percentile values: these are useful for creating quartiles (Cut points for 4 equal groups) or Percentiles of various sizes.
  3. Dispersion: you should already be familiar with most of the measures of dispersion, particularly the Minimum and Maximum, but there is also the Std. deviation (SD) and Variance (which is just SD2). We’ll learn about the S. E. Mean later.
  4. Central tendency: similarly, you should also be familiar with all of the measures of central tendency: Mean, Median, Mode, and Sum.
  5. Distribution: you should also be familiar with both Skewness and Kurtosis and later we will learn what those values mean and how that helps us test for normality.
  6. Normality: lastly, there is a statistical test for normality called the Shapiro-Wilk test that we will learn about later.

Describing one variable split by another variable

Sometimes we want to get the descriptive statistics for one variable across multiple groups of another variable. Usually, this is a continuous variable split by a categorical variable. In that case, move your continuous variable to the Varables box and the variable you want split by categories in to the Split by box.