A Level Psychology OCR Practice Exam

What type of data encompasses measurements that include no negative values?

1. Nominal data

2. Ordinal data

3. Interval data

4. Ratio data

The correct answer is: Ratio data

The correct answer is ratio data. This type of data is distinguished by the presence of a true zero point, which indicates the absence of the quantity being measured. Because of this true zero, ratio data can only take on non-negative values, making it impossible for any measurement to be negative. For example, in the context of height or weight, a measurement of zero indicates no height or weight, respectively. Nominal data refers to categorical data without any inherent order, while ordinal data also involves categories but with a meaningful order; however, neither can ensure that values are non-negative since they do not involve measurements in the quantitative sense. Interval data, while it does feature ordered values, lacks a true zero point and can represent negative values (for instance, temperature in Celsius can dip below zero). Therefore, ratio data is the only type of data that fits the criterion of encompassing measurements with no negative values, as it allows for meaningful comparisons and mathematical operations based on the true zero.