Consider a scale from 1 to 100 for locating consumers according to the characteristic “attitude toward department stores.” Each respondent is assigned a number from 1 to 100 indicating the degree of (un)favorableness, with 1 = extremely unfavorable, and 100 = extremely favorable.

Ratio scales

interval scale

A ratio scale is the highest level of measurement and allows the researcher to identify or classify objects, rank order the objects, and compare intervals or differences. Temperature scales such as Celsius and Fahrenheit are examples of interval scales.

There are four levels of measurement – nominal, ordinal, and interval/ratio – with nominal being the least precise and informative and interval/ratio variable being most precise and informative.

One way to deal with this notion is to revise the simple true score model by dividing the error component into two subcomponents, random error and systematic error.

There are four main types of reliability….Table of contents

• Test-retest reliability.
• Interrater reliability.
• Parallel forms reliability.
• Internal consistency.
• Which type of reliability applies to my research?

True Score Theory is a theory about measurement. Essentially, true score theory maintains that every measurement is an additive composite of two components: true ability (or the true level) of the respondent on that measure; and random error. …

In statistics and psychometrics, reliability is the overall consistency of a measure. A measure is said to have a high reliability if it produces similar results under consistent conditions.

Reliability can be estimated by comparing different versions of the same measurement. Validity is harder to assess, but it can be estimated by comparing the results to other relevant data or theory. Methods of estimating reliability and validity are usually split up into different types.

To calculate MTBF, divide the total number of operational hours in a period by the number of failures that occurred in that period. MTBF is usually measured in hours. For example, an asset may have been operational for 1,000 hours in a year. Over the course of that year, that asset broke down eight times.

There are two types of reliability – internal and external reliability. Internal reliability assesses the consistency of results across items within a test. External reliability refers to the extent to which a measure varies from one use to another.

Test reliability. Reliability refers to how dependably or consistently a test measures a characteristic. If a person takes the test again, will he or she get a similar test score, or a much different score? A test that yields similar scores for a person who repeats the test is said to measure a characteristic reliably.

Reliability Testing is a software testing process that checks whether the software can perform a failure-free operation for a specified time period in a particular environment. The purpose of Reliability testing is to assure that the software product is bug free and reliable enough for its expected purpose.

The most known concept to define reliability is: “Probability that an asset or system operates without failing during a given period of time under some operation conditions previously established.” Sometimes, this concept is wrongly used due to the particular use given to the word failure.