| Standard 5-1 : NCES Statistical Standards |

| | In the case of a stratified **sample** design with disproportionate **sample** allocation, the use of appropriate case weights will reduce the biases in means and totals, but will not necessarily correct biases in standard errors. |

| | When estimates are compared to one another based on exploratory research and presented in descriptive reports, observed deviations in either direction are of interest and the rejection region lies within both tails of the **distribution** of the test statistic. |

| | If a statistically significant difference for a total group under study is observed, but similar subgroup differences of the same magnitude are associated with smaller **sample** sizes and/or larger standard errors and are not statistically significant, this may be noted. |

| nces.ed.gov /statprog/2002/std5_1.asp (1323 words) |