Answer:
Standard deviation is a number that tells you how measurements for a group are spread out from the average, aka the mean.
<u>Answer:
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The study carried out by Dr. Xu is a randomized controlled study.
<u>Explanation:</u>
- For the sake of determination of how the results of the students change by doing certain changes to the examination pattern, Dr. Xu devised that the change is considerably evident.
- Dr. Xu provided and intervention in the process of exam in the form of guides which helped the students to score better later. Hence, from the standard of conduct of the study, it can be said to be a randomized controlled study.
The answer for this question is: Appalachian
The Appalachian region has the perfect temperature that allows many type of vegetations to grow.
Not only that, the soil in this region also contained a lot of substances that are very nutritious for plants and could very much help in their growing development.
The European nations that established colonies in South America were Spain and Portugal.
