Term
| What is the difference between a positive and negative control? |
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Definition
| A positive control is a control where a positive and known result is expected. A negative control is a control where no result is expected. |
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Term
| When you test for probability what are you testing? |
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Definition
| You are testing for the probability that the results were derived from chance. Probability <0.5 means that the results will be recreated by chance <5 % of the time, and the alternate hypothesis can be accepted. |
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Term
| What is the formula for calculating Chi-Square values? |
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Definition
| x2 = SUM OF(observed-expected)^2/expected |
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Term
| How do you calculate the degrees of freedom for a Chi-Square test? |
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Definition
| DF = number of categories (ex. dry sponges v. wet sponges = 2 categories) - 1 |
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Term
| What is the difference between a Type I and Type II error? |
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Definition
In a Type I error, results are percieved as significant when they are actually not.
In a Type II error, results are not percieved as significant when they actually are. |
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Term
| What are ordinal variables? |
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Definition
| They are categories with natural ordering (ex. grades -> A>B>C, etc.) |
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Term
| What is power in statistics? How can you increase it? |
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Definition
| Power is the reliability of the experiment. To increase power, you can increase the sample size, lower the cut off P, etc. |
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