There are many factors that may hinder or aid a particular population. Often tim

Question

There are many factors that may hinder or aid a particular population. Often times when put under sudden stress, either by environmental factors such as a harsh winter, or a manmade one like a chemical spill, the likelihood that genetic rescue would occur generally declines if a population is not well adapted. One such example of stress that we will be researching is predation. When a given population becomes stressed due to high rates of predation, the likelihood of genetic rescue occurring declines. The reason why we chose predation as the stress a population of deer can also be considered an example of predation inducing stress. This is important because it can allow us to begin to hypothesize effects of predation on genetic rescue allowed to get an idea of what might occur in terms of the rate of genetic rescue and the flow of genetic material in many stressed populations Rationale: Predation is typically defined as "the prey on one animal by another". However, for the purposes of this experiment, predation will also be defined as human harvesting; where a portion is considered to increase the rate of mortality in both adults and offspring, which adds a notable

Explanation / Answer

A well-designed and constructed experiment will be robust under questioning, and will focus criticism on conclusions, rather than potential experimental errors. A sound experimental design should follow the established scientific protocols and generate good statistical data.

As an example, experiments on an industrial scale can cost millions of dollars. Repeating the experiment because it had poor control groups, or insufficient samples for a statistical analysis, is not an option. For this reason, the design phase is possibly the most crucial.

Design of Experiment Basic

With most true experiments, the researcher is trying to establish a causal relationshipbetween variables, by manipulating an independent variable to assess the effect upon dependent variables.

In the simplest type of experiment, the researcher is trying to prove that if one event occurs, a certain outcome happens.

For example;

"If children eat fish, their IQ increases."

This is a good hypothesis and, at first glance, appears easily testable. The problem is that, in any solid experimental design, the opposite (contrapositive) should also be true. The design of experiment dictates that, if a certain event does not occur, the tested outcome will not happen, a subtle but crucial factor.

The reason for this is that it ensures that there is a genuine causal relationship between the independent and dependent variables.

Therefore, the following statement should also be true.

"If children do not eat fish, then their IQ will not increase."

The first statement is fairly easy to study, relying upon feeding children varying amounts of fish, and measuring their IQ.

However, it is much more difficult to test the second statement. The only way to test it properly is not to feed the children fish. It is impossible to use the same children, so a compromise must be reached, and the researcher must use two different groups of children.

The problem is that it is impossible to have two identical groups, and the Design of Experiment must take this into account. The researcher must understand that there are always going to be differences between the groups

This is why a solid experimental design should have extremely strong controls, and meticulous operationalization. Random groups are the best way of ensuring that the groups are as identical as possible.

In the fish example, all of the children could eat the same diet, but the tested group could be given extra fish supplements. Randomizing the groups tries to balance out the differences between individuals, and also removes any potential experimental bias.

Internal vs. External Validity

The second problem is that you have no idea whether other factors could influence the result.

Obviously, it is unethical to starve children, but other foods could have a significantinfluence upon IQ.

It is difficult to monitor what food the children are eating at home, leading to a potential confounding variable.

In addition, children from different schools may have a varying quality of teaching, potentially influencing the results.

These are just some of the factors potentially affecting the experiment, and any design of experiment must try to filter out the true results from the experimental 'noise'.

In an ideal 'True Experiment' situation, you would lock all of the children in a laboratory, subjecting them all to the same conditions. The researcher could then ensure that all variables are controlled, except for the independent variable, eating fish.

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