The strength of the correlation is determined by the correlation coefficient, r. It is sometimes referred to as the Pearson product moment correlation coefficient in honor of its discoverer, Karl Pearson, who first introduced the term in 1900. There are three different formulas used to calculate this number: the raw score formula, the deviation formula or the covariance formula.
Know MoreThe correlation coefficient measures the degree of a linear relationship between two variables. These variables are usually labeled X and Y. Correlation is similar to regression, but different in how it relates two variables to one another. Regression is concerned with using one variable to predict another. Correlation looks at the relationship between the two variables. The correlation coefficient has either a positive or a negative sign. The sign describes the direction of the relationship between the two variables. A positive sign and a positive correlation coefficient indicates that when the value of one variable increases, the value of the other increases as well. Similarly, if the value of one variable decreases, the value of the other variable decreases if the correlation coefficient is positive. If the correlation coefficient is negative, when the value of one variable increases, the value of the other variable decreases and vice versa.
Learn MoreIn math, outliers are observations or data points that lie an abnormal distance away from all of the other values in a sample. Outliers are usually disregarded in statistics because they can skew calculations and cause the final statistical analyses to be invalid.
Full Answer >A confidence interval indicates how uncertain a researcher is about an estimated range of values. A 99 percent confidence interval indicates that if the sampling procedure is repeated, there is a 99 percent chance that the true average actually falls between the estimated range of values.
Full Answer >In probability, disjoint events are mutually exclusive, meaning that if one of the possible disjoint events occurs, the other cannot occur. For example, when a driver reaches an intersection, she may turn left or right, or go straight, but may not turn and go straight. Turning and driving straight are therefore disjoint events.
Full Answer >The Hardy-Weinberg equations calculate the genetic variation and allele frequencies of a population at equilibrium. They are p + q = 1 and p^2+ 2pq + q^2 = 1 where p is the frequency of the "A" allele and q is the allele frequency for the "a" allele.
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