What is a class interval in statistics
Next page:Types of variables Upwards:Data preparation Previous page:Grouped data & nbsp index
For practical reasons, it is often useful to assign variables with a large number of characteristics classify, i.e. grouping several values into one value range (classified variable). This can already be done during the data collection or during the later statistical analysis.
The choice of classes and their limits largely depends on content-related criteria. Formally, a classification must meet three requirements: uniqueness, exclusivity and completeness. A classification is unambiguous if every empirically occurring value can be assigned to a class. It is exclusive if each value falls into only one class and not into several classes. Finally, it is complete when both of the previous conditions apply, i.e. there is no value that cannot be assigned to any class. In particular, the class boundaries must be defined in such a way that it is clear which class is assigned a value that falls exactly on the class boundary.
From a statistical point of view, it is advantageous if the Class widths are the same size and open classes be avoided. However, these claims cannot always be honored for the following reasons:
- The class width should be chosen sufficiently large to prevent individual classes from being filled too small. To ensure this, it may be necessary in some cases to increase the widths of individual classes deviating from the selected classification interval. Or if many values fall into one class, it may be necessary to reduce certain classes (see the income class 1,800-2,000 DM in the example).
- Sometimes it is also unknown which value the examined characteristic can assume maximally or minimally. In this case, the top or bottom class must remain open at the top or bottom (cf. the income class 7,500 DM and more in the example).
How one can treat the classified variable in the subsequent statistical analysis also depends on these (content-related) decisions. In the second example (phases of life), the individual classes are viewed as categories that are different from one another and, at best, have a hierarchy. In the first example (average age) you should actually go back to the original values. If these are not available, the middle of the class is used as an estimate for the original values combined in the class.
notation: be the upper limits of the classes . Square and round brackets then indicate whether the respective class boundary should still belong to the class interval (square brackets) or not (round brackets). says, for example, that the second class has all values of including to below includes: . In other words: the lower limit belongs to this class, but the upper limit does not. The square brackets in front and after finally indicate that no open classes are used at the lower and upper end of the classification. You are therefore certain that the range of values of the variables to be classified is from to is enough and no smaller or larger values can appear.
Next page:Types of variables Upwards:Data preparation Previous page:Grouped data & nbsp index HJA 2001-10-01
- Which is the best travel insurance
- Bigrock is good for buying domain names
- When were Hoeschen invented?
- Are sweets bad for children
- Who is responsible for Iron Maiden's Eddie
- How can the space-time continuum bend?
- Are doctors biased against fat patients
- Corruption is getting worse in Indonesia
- How powerful is Turkey
- How big were the ancient Roman prisons
- What are some good streaming audio servers
- What are some software engineering project ideas
- What if India decided to invade Indonesia?
- Are tomboy just reverse drag queens
- Which social media site is the safest
- How do you live a better life
- What is ecommerce security
- What is a Halim seed
- What are some traditional chinese desserts
- What's your Christmas routine
- How do you get dementors
- Which keto pills are effective
- What is Asia's most beautiful country
- Can I be a NASA scientist?
- Where do illegal weapons come from?
- What is an efficient algorithm
- How does the video game industry work
- Foreign law firms hire Indian lawyers
- What if everyone on earth became a vegetarian?
- How beautiful you look
- Is it unhealthy to eat raw ramen?
- Why should i buy things online
- How do grocery stores buy products
- Which Quora blog has the most posts