# Biology

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When is a measurement valid?
when it measures what it is supposed to be measuring
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When is a result accurate?
when it is close to the true value
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What are precise results?
when repeat measurements are consistent/agree closely with each other
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What is repeatability?
how precise repeated measurements are when they are taken by the same person, using the same equipment, under the same conditions
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What is reproducibility?
how precise repeated measurements are when they are taken by different people, using different equipment
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What is the uncertainty of a measurement?
the interval within which the true value is expected to lie
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Define measurement error
the difference between a measured value and the true value
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What type of error is caused by results varying around the true value in an unpredictable way?
random error
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What is a systematic error?
a consistent difference between the measured values and true values
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What does zero error mean?
a measuring instrument gives a false reading when the true value should be zero
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Which variable is changed or selected by the investigator?
independent variable
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What is a dependent variable?
a variable that is measured every time the independent variable is changed
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Define a fair test
a test in which only the independent variable is allowed to affect the dependent variable
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What are control variables?
variables that should be kept constant to avoid them affecting the dependent variable
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## Other cards in this set

### Card 2

#### Front

when it is close to the true value

#### Back

When is a result accurate?

### Card 3

#### Front

when repeat measurements are consistent/agree closely with each other

### Card 4

#### Front

how precise repeated measurements are when they are taken by the same person, using the same equipment, under the same conditions

### Card 5

#### Front

how precise repeated measurements are when they are taken by different people, using different equipment