the variables that are kept the same in order to test the relationships between the independent and dependent variables

the variable for which quantities are manipulated (selected or changed) by the experimenter

how close the experimental result obtained is to the accepted, or ‘true’, value of the particular quantity subject to measurement

the test that ensures the results are due to the independent variable and not other factors

how closely two or more measurements agree with other.

used an incorrect quantity of a chemical, timed an experiment inconsistently, or not followed the method carefully enough.

Affects the accuracy of a measurement and causes reading to differ from the true value by a consistent amount each time resulting in a measurement is too high or too low. Often due to equipment issues such as poorly calibrated equipment.

affect the precision of a measurement and are present in all measurements except for measurements involving counting. Can be reduced by obtaining more or repeated measurements, calculating a mean or refining the method.

the closeness of agreement between independent results obtained with the same method on identical test material, under the same condition

to the closeness of agreement between independent results obtained with the same method on identical test material but under different conditions (different operators, different apparatus and/or different laboratories

the likelihood that the experiment will generate the same results when performed under exactly the same conditions.