Question

select all the correct answers. a colorimeter is an instrument used for chemical analysis by comparing a liquid’s color with standard colors. in an experiment, a scientist used two colorimeters and noted the readings. the first colorimeter showed consistent readings that were five points lower than the actual reading. the second colorimeter provided readings that were the same as the actual reading. which two statements are implications of these readings? the first colorimeter is reliable but not valid. the second colorimeter is valid and reliable. both the colorimeters are reliable and valid. the readings of the first colorimeter can be used without repeating the experiment. the readings of the second colorimeter aren’t reliable and can’t be used for the experiment.

Explanation:

1. For "The first colorimeter is reliable but not valid": Reliability means consistent results. The first colorimeter has consistent readings (reliable) but is 5 points lower than actual (not valid, as validity is measuring what it should). So this is correct.
2. For "The second colorimeter is valid and reliable": It gives readings same as actual (valid) and since it's consistent (implied by giving same as actual, no inconsistency shown), it's reliable. So this is correct.
3. "Both the colorimeters are reliable and valid": First is not valid, so this is wrong.
4. "The readings of the first colorimeter can be used without repeating the experiment": Even though it's reliable, it's not valid (systematic error), so readings need adjustment or repetition to correct, so this is wrong.
5. "The readings of the second colorimeter aren't reliable and can't be used for the experiment": Second is valid and reliable, so this is wrong.

Answer:

A. The first colorimeter is reliable but not valid.
B. The second colorimeter is valid and reliable.