A test of intelligence is given to a subject. The subject scores 110 on the first administration. Six months later, the same sub
ject is given the same test again and receives a score of 75. After another six months has passed, the subject is given the test one last time and receives a score of 138. What conclusions can be drawn from these scores?The scores are not valid.
The test supposed to be measuring intelligence. We can assume that the intelligence of most people relatively stable (will not change too much over a short amount of time), and can expect it should go upward with brain growth and education. But the test seems to give a huge decrease from the first and second results. Then the third result is a huge increase that even higher than the first test.
We don't know the true value of the subject, but seeing the huge gap for every repetition we can tell that the test result lacks precision.
