Inferential Statistics | An Easy Introduction & Examples

While descriptive statistics summarize the characteristics of a data set, inferential statistics help you come to conclusions and make predictions based on your data.

When you have collected data from a sample, you can use inferential statistics to understand the larger population from which the sample is taken.

Inferential statistics have two main uses:

  • making estimates about populations (for example, the mean SAT score of all 11th graders in the US).
  • testing hypotheses to draw conclusions about populations (for example, the relationship between SAT scores and family income).

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Interval Data and How to Analyze It | Definitions & Examples

Interval data is measured along a numerical scale that has equal distances between adjacent values. These distances are called “intervals.”

There is no true zero on an interval scale, which is what distinguishes it from a ratio scale. On an interval scale, zero is an arbitrary point, not a complete absence of the variable.

Common examples of interval scales include standardized tests, such as the SAT, and psychological inventories.

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Ordinal Data | Definition, Examples, Data Collection & Analysis

Ordinal data is classified into categories within a variable that have a natural rank order. However, the distances between the categories are uneven or unknown.

For example, the variable “frequency of physical exercise” can be categorized into the following:

1. Never 2. Rarely 3. Sometimes 4. Often 5. Always

There is a clear order to these categories, but we cannot say that the difference between “never” and “rarely” is exactly the same as that between “sometimes” and “often”. Therefore, this scale is ordinal.

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Nominal Data | Definition, Examples, Data Collection & Analysis

Nominal data is labelled into mutually exclusive categories within a variable. These categories cannot be ordered in a meaningful way.

For example, preferred mode of transportation is a nominal variable, because the data is sorted into categories: car, bus, train, tram, bicycle, etc.

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Central Tendency | Understanding the Mean, Median & Mode

Measures of central tendency help you find the middle, or the average, of a dataset. The 3 most common measures of central tendency are the mode, median, and mean.

  • Mode: the most frequent value.
  • Median: the middle number in an ordered dataset.
  • Mean: the sum of all values divided by the total number of values.

In addition to central tendency, the variability and distribution of your dataset is important to understand when performing descriptive statistics.

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Levels of Measurement | Nominal, Ordinal, Interval and Ratio

Levels of measurement, also called scales of measurement, tell you how precisely variables are recorded. In scientific research, a variable is anything that can take on different values across your data set (e.g., height or test scores).

There are 4 levels of measurement:

  • Nominal: the data can only be categorized
  • Ordinal: the data can be categorized and ranked
  • Interval: the data can be categorized, ranked, and evenly spaced
  • Ratio: the data can be categorized, ranked, evenly spaced, and has a natural zero.

Depending on the level of measurement of the variable, what you can do to analyze your data may be limited. There is a hierarchy in the complexity and precision of the level of measurement, from low (nominal) to high (ratio).

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Descriptive Statistics | Definitions, Types, Examples

Descriptive statistics summarize and organize characteristics of a data set. A data set is a collection of responses or observations from a sample or entire population.

In quantitative research, after collecting data, the first step of statistical analysis is to describe characteristics of the responses, such as the average of one variable (e.g., age), or the relation between two variables (e.g., age and creativity).

The next step is inferential statistics, which help you decide whether your data confirms or refutes your hypothesis and whether it is generalizable to a larger population.

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What Is a Likert Scale? | Guide & Examples

A Likert scale is a rating scale used to measure opinions, attitudes, or behaviors.

It consists of a statement or a question, followed by a series of five or seven answer statements. Respondents choose the option that best corresponds with how they feel about the statement or question.

Because respondents are presented with a range of possible answers, Likert scales are great for capturing the level of agreement or their feelings regarding the topic in a more nuanced way. However, Likert scales are prone to response bias, where respondents either agree or disagree with all the statements due to fatigue or social desirability or have a tendency toward extreme responding or other demand characteristics.

Likert scales are common in survey research, as well as in fields like marketing, psychology, or other social sciences.

Likert-Scale-5-point-scalesLikert-Scale-7-point-scales

Download Likert scale response options

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What Is Qualitative Research? | Methods & Examples

Qualitative research involves collecting and analyzing non-numerical data (e.g., text, video, or audio) to understand concepts, opinions, or experiences. It can be used to gather in-depth insights into a problem or generate new ideas for research.

Qualitative research is the opposite of quantitative research, which involves collecting and analyzing numerical data for statistical analysis.

Qualitative research is commonly used in the humanities and social sciences, in subjects such as anthropology, sociology, education, health sciences, history, etc.

Qualitative research question examples
  • How does social media shape body image in teenagers?
  • How do children and adults interpret healthy eating in the UK?
  • What factors influence employee retention in a large organization?
  • How is anxiety experienced around the world?
  • How can teachers integrate social issues into science curriculums?

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