dentify the symbols used for each of the following: (a) sample standard deviation (b) population standard deviation (c) sample variance (d) population variance
The symbol for sample standard deviation is (1) Os s2
The symbol for population standard deviation is (2) Os s?
The symbol for sample variance is (3) OS
The symbol for population variance is (4)
The Correct Answer and Explanation is:
Here are the correct statistical symbols for each of the terms listed:
(a) Sample standard deviation: s
(b) Population standard deviation: σ (Greek letter sigma)
(c) Sample variance: s²
(d) Population variance: σ²
Explanation
In statistics, standard deviation and variance are measures used to quantify the spread or dispersion of a set of data points. These measures are essential in understanding how much the data deviates from the mean (average).
Sample Standard Deviation (s):
The symbol s is used to denote the standard deviation calculated from a sample of the population. A sample is a subset of the entire population and is often used when it’s impractical or impossible to study the entire population. The formula involves dividing the sum of squared deviations from the sample mean by (n – 1), where n is the sample size. The use of (n – 1) instead of n is called Bessel’s correction, and it corrects the bias in the estimation of the population standard deviation from a sample.
Population Standard Deviation (σ):
The symbol σ (Greek lowercase sigma) represents the population standard deviation. It measures the average distance of each data point in the entire population from the population mean. Unlike the sample standard deviation, it divides by N (the population size) because all data points are included.
Sample Variance (s²):
Variance is simply the square of the standard deviation. Thus, the sample variance is denoted as s². It provides a measure of how data points in a sample spread around the sample mean. Since it is based on the sample standard deviation, it also uses Bessel’s correction.
Population Variance (σ²):
Similarly, population variance is the square of the population standard deviation and is denoted as σ². It indicates how much the entire population’s data points vary from the population mean.
Using correct symbols helps in clear communication of whether you are analyzing data from a sample or the whole population, which is critical for valid statistical conclusions.
