One way to get consistent, valid data is to:
be sure that instruments are calibrated properly.
use simple instruments to make measurements.
select the best data to place into data tables.
make the measurements as quickly as possible

Answer;

be sure that instruments are calibrated properly.

One way to get consistent, valid data is to be sure that instruments are calibrated properly.

Explanation;

In order for assessments or experiments to be sound, they must be free of bias and distortion. Reliability and validity are two concepts that are important for defining and measuring bias and distortion.

Reliability refers to the extent to which assessments are consistent. Another measure of reliability is the internal consistency of the items.

Validity refers to the accuracy of an assessment; whether or not it measures what it is supposed to measure.

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle