No, for a test to be valid, it must also be reliable. Reliability refers to the consistency of the test results, while validity refers to the accuracy of the test in measuring what it is supposed to measure. A test cannot be valid if it is not reliable.
In my view reliable test is always valid.
The polygraph test is not "proof-positive". The polygraph test is not completely unreliable.
No it is a urine test to look for heavy alcohol consumption. It is pretty unreliable though.
There is no such valid test, so I would definitely question it.
Yes, it would be a valid test.
No
Reliable indicates that each time the experiment is conducted, the same results are obtained (accuracy). Valid indicates the experiment (or test) has controlled variables and used an appropriate method/model.
Yes sure. It is valid. It will shows the how fast you are thinking.
To be valid, an experiment must not include bias, confounding variables, or unreliable measures in order to accurately assess the cause-and-effect relationship between variables.
LSAT, MCAT, so on
To ensure that the results are valid. That's the whole point of a science test. The test must be able to be repeated and have the same result to start being considered valid.