Acres to Hectares Conversion. There are 0.404685642 hectares in an acre. In other words, it is about 40 percent of a hectare. To find out how many hectares in acres, multiply by the conversion factor or instead, use the converter below. Acre is an imperial and US customary area measurement unit which equals to 43560 square feet.
intervention study. testing an hypothesized epidemiological cause-effect relationship by intervening in a population and modifying a supposed causal factor and measuring the effect of the change.
Pilot studies, sometimes called feasibility studies, mock studies, or dry-run studies, involving human subjects (no matter how small the sample size is) require the same scrutiny as full-scale research projects and therefore, must be submitted for IRB review and approval.