at least 3/43/43/4 of the data lie within two standard deviations of the mean, that is, in the interval with endpoints x¯±2sx¯±2s\bar{x}\pm 2s for samples and with endpoints μ±2σμ±2σ\mu \pm 2\sigma for populations; at least 8/98/98/9 of the data lie within three standard deviations of the mean, that is, in the interval with endpoints x¯±3sx¯±3s\bar{x}\pm 3s for samples and with endpoints μ±3σμ±3σ\mu \pm 3\sigma for populations; at least 1−1/k21−1/k21-1/k2 of the data lie within kkk standard deviations of the mean, that is, in the interval with endpoints x¯±ksx¯±ks\bar{x}\pm ks for samples and with endpoints μ±kσμ±kσ\mu \pm k\sigma for populations, where kkk is any positive whole number that is greater than 111.