Archaeologists plan to examine a sample of 2-meter-square plots near an ancient Greek city for artifacts visible in the ground.
They choose separate samples of plots from floodplain, coast, foothills, and high hills. What kind of sample is this? A. A stratified random sample. B. A voluntary response sample. C. A simple random sample. D. None of the above.
Stratified random sampling is a method of sampling that involves the division of the population into smaller groups. These groups are the known as strata. Different strata have different characteristics. In this example, the different strata would be the samples of plots from floodplain, coast, foothills, and high hills.
Let y equal number of pushups a day. When x = 1, y = 8. When x = 2, y = 10. 10 is a factor of 30. Multiply y by 3. However, since x increases by 1 when y increases by 2, multiply x by 6 (2*3). That equals 12. Therefore, when x = 12, y = 30.