A group of blood relatives from more than one nuclear family who live together form which kind of household?

When researchers study the same sample over a long period of time, as was done in a number of longitudinal studies that were launched in the 1920s and 1930s, their results may be limited by all of the following phenomena except

a. lack of measurement equivalence b. attrition of participants c. practice effects d. lack of continuity

Both the Tuskegee Experiment and the Baltimore Lead Paint Study violated the principle of justice by

A) only using prisoners from local penitentiaries. B) requiring participants to complete mandatory participation. C) asking persons to recruit others to participate in the study. D) putting groups with limited or diminished autonomy at risk.