Which best describes the purpose of a controlled experiment? A)to make sure the results of the experiment support the hypothesis B)to prevent a dangerous condition resulting from a reaction C)to examine whether one variable causes a change in another D)to prevent an undesired change in a variable

Weights of golden retriever dogs are normally distributed. samples of weights of golden retriever dogs, each of size nequals15, are randomly collected and the sample means are found. is it correct to conclude that the sample means cannot be treated as being from a normal distribution because the sample size is too small? explain.

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

The “ecological footprint” left by a citizen of a developed nation is about four times larger than that left by a citizen of a developing nation. why is this the case?