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9 Cards in this Set
- Front
- Back
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What is a Poisson distribution?
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applies if the number of events is very large but the positive outcome is small
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What is a Gaussian distribution?
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normal bell curve, symmetrical around the mean; applies to a large number of events when expected positive outcome is large
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What distribution does nuclear medicine use, Poisson or Gaussian?
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technically follows a Poisson but with any sample over 20 then the distribution will follow Gaussian
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What is the standard deviation equation?
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SD = √(∑(x-(x)) ̅ ^2/(N-1)
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On a normal curve the % of values that fall within 1 SD is _____
2 SD is _____ 3 SD is _____ |
On a normal curve the % of values that fall within 1 SD is 68.3%
2 SD is 95.5% 3 SD is 99.8% |
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How do you calculate % of error?
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100% x (expected – measured/ expected)
Example: Co57 at 5.72 mCi, measured in dose calibrator @ 5.53 mCi; % error: 5.72 – 5.53/5.72 x 100 = 3.22% |
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What is important to remember about the difference between accuracy and precision?
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accuracy is the closeness of the values to the true values and precision is the ability to produce results. you can produce good results but they may not be accurate
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What is the chi-square test?
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The measure of discrepancy that may exist in a data group. Goodness of fit, measure of observed frequency vs. expected frequency.
must be measured against a chi-square distribution table |
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What is the Chi-square formula?
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x^2= (Σ(x-ˉx)^2)/(ˉx)
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