Construction Health and Safety Technician (CHST) 2025 – 400 Free Practice Questions to Pass the Exam

The concept of statistical "variance" is a crucial measurement in understanding the distribution of data points within a dataset. Variance quantifies the degree to which individual data values differ from the mean (average) value. Specifically, it provides insights into how much the values are dispersed or spread out across the average, making it a vital statistic for comprehending data variability.

When variance is calculated, it reflects the average of the squared differences between each data point and the mean. This means that a high variance indicates a wide spread of values, while a low variance suggests that the data points are more clustered around the mean. This quantitative measure is essential in fields like construction health and safety, where variations in data can have significant implications for risk assessment and management practices.

In contrast, the other options focus on different statistical measures. The average value of a dataset identifies a central tendency but does not convey how spread out the data points are. The total number of data points simply counts the observations without indicating any variation between them, and the median provides the middle value but does not measure variability. Thus, understanding variance is fundamental for analyzing data spread effectively.