In order to make and successfully obtain a valid test
there are some conditions which must necessarily happen. These conditions are:
fairness of the test, reliability of the test and accuracy. Fairness of the
test is obtained when only the desired independent variable changes whilst the
control variables are kept constant. In my experiment I needed to be careful
and precise in cutting the potato to my previously chosen lengths. All my other
variables had been kept the same such as substrate concentration, temperature,
same tuber and so on, in order to consider my experiment a fair test.


order for a test to be considered reliable, results have to be similar and it
would be ideal to repeat the investigation more than once in order to create a
mean between the results. I repeated the test for three times, reproducing each
time the same experiment with the same equipment and same variables.