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