S D.

In probability and statistics, the standard deviation is the most common measure of statistical dispersion. Simply put, standard deviation measures how spread out the values in a data set are. More precisely, it is a measure of the average distance of the data values from their mean. If the data points are all close to the mean, then the standard deviation will be low (closer to zero). If many data points are very different from the mean, then the standard deviation is high (further from zero). If all the data values are equal, then the standard deviation will be zero.

The standard deviation is defined as the square root of the variance. This means it is the root mean square (RMS) deviation from the arithmetic mean. The standard deviation is always a positive number (or zero) and is always measured in the same units as the original data. For example, if the data are distance measurements in meters, the standard deviation will also be measured in meters.

– In other words, the standard deviation of a discrete uniform random variable X can be calculated as follows: For each value xi calculate the difference between xi and the average value. Calculate the squares of these differences. Find the average of the squared differences. This quantity is the variance σ2. Take the square root of the variance.

Example. Our example will use the ages of four young children: { 5, 6, 8, 9 }. Step 1. Calculate the mean/average :

Step 2. Calculate the standard deviation :

Replacing N with 4

Venn Diagram The Venn Diagram is made up of two or more overlapping circles. It is often used in mathematics to show relationships between sets.

BAR DIAGRAM

HISTOGRAM The most common form of the histogram is obtained by splitting the range of the data into equal-sized bins (called classes). Then for each bin, the number of points from the data set that fall into each bin are counted. That is Vertical axis: Frequency (i.e., counts for each bin) Horizontal axis: Response variable

EPIDEMIC CURVE Depending on the information available in a particular outbreak situation, an epi curve can provide insight into the pattern of disease spread, the magnitude of the outbreak, the time trend involved, the outlying cases, the period of exposure and/or the incubation period of the organism involved. All of these pieces of information can be valuable. For example, an epidemic curve may allow you to see that the outbreak appears to be from a point source, or that it is ongoing.

Frequency polygon A frequency polygon is a graphical display of a frequency table. The intervals are shown on the X-axis and the number of scores in each interval is represented by the height of a point located above the middle of the interval. The points are connected so that together with the X-axis they form a polygon.