In statistics, the standard deviation (SD, also represented by the Greek letter sigma σ or s) is a measure that is used to quantify the amount of variation or dispersion of a set of data values. A standard deviation close to 0 indicates that the data points tend to be very close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the data points are spread out over a wider range of values.
The standard deviation of a random variable, statistical population, data set, or probability distribution is the square root of its variance. It is algebraically simpler, though in practice less robust, than the average absolute deviation. A useful property of the standard deviation is that, unlike the variance, it is expressed in the same units as the data. There are also other measures of deviation from the norm, including mean absolute deviation, which provide different mathematical properties from standard deviation.
Standard deviation is a widely used measure of variability or diversity used in statistics and probability theory.
Standard Deviation(s) may also refer to:
"Standard Deviation" is the third episode of the first season of the American period drama television series Masters of Sex. It originally aired on October 13, 2013 in the United States on Showtime.
In 1945, William Masters (Michael Sheen) shows Barton Scully (Beau Bridges) an experiment he is conducting with rabbits. He then reveals to Scully that he wants to stop studying animal sexuality and move on to humans, claiming that everyone, including Bill himself, is clueless about sex. Time transitions back to February 1957, where an engaged college student (Mae Whitman) is consulting Bill about contraception. Not even aware of where her cervix is, she is clearly uneducated about sex.
Virginia Johnson (Lizzy Caplan) eagerly tells Bill about the prostitutes from the brothel that have agreed to partake in their study. She is disappointed by Bill treating her like his secretary, when she prefers to be considered his assistant. Betty (Annaleigh Ashford) confronts Bill about his refusal to reverse her tubal ligation. He eventually agrees to do it, but still believes it is not a good idea.