Which of the following best specifies the purpose of error bars on a graph? to show the mean of a data set to identify the independent variable to give a visual display of measurement precision to indicate the total number of measurements that are made

to give a visual display of measurement precision

Explanation:

Error bars on graphs indicate how far the measured value is from the true value. In other words it is a measure of how precise the reported value is and gives the uncertainty of measurement.

It is depicted as a vertical line which extends above (positive direction) and below(negative) the measured value. For example in the measurement of length, if one of the reported value is 23 ± 0.1 mm then, the ± 0.1 would be the deviation (uncertainty) in the measurement.

yes the answer is total mass in unchanged   : )