I believe the year in question is not 1970 but 1790.
The answer to the question is South Carolina. Given its small size compared to the other states they had the huge number of slaves about 65%. The 65% were African-American slaves. The slaves population in South Carolina grew in connection to their rice culture success.
The research error described above is an example of selection bias.
Selection bias takes place when, from a population of interest, a group of individuals is selected in order to construct a sample but without a proper randomization. The result is a sample which is not representative of the underlying population.
According to the example, the target population of the research comprises all students but the sample only includes boys. Hence, selection has not been random because it followed a gender criteria, and the results obtained using it cannot be applicable to the whole population because they are affected by a selection bias.
Conservation allows scarce resources to bounce back from udder demise. Without conservation, many plants and animals would go extinct.
