Point estimate - a descriptive measure computed from the sample that intends to directly predict the probable location of a population parameter. Statistical estimates are prone to both random and systematic sources of error, and should not be viewed as constants (cf. parameters). Examples of point estimates are the sample mean ("x bar") as an estimate of the population mean (), the sample variance as an estimate of the population variance ("sigma squared"), and the sample relative risk ("RR hat") as an example of the population relative risk.