the sign test?

Question

what is the sign test, and how do i use it?

Answer 1

get a saw, go to the closest street sign cut it off, then start running round the neighboorhood screaming i am the ruler of said street... enjoy!

Answer 2

The Sign Test is a nonparamteric test that may be of use when it is only necessary (or possible) to know if observed differences between two conditions are significant. That is to say, with appropriate use of the sign test, it would be possible to determine if X is really "more" than Y, or however the conditions are arranged.
The sign test is structured so that plus (+) and minus (-) "signs" are used to denote change in magnitude, as opposed to a any attempt at quantitative measurement.

All the best.

Answer 3

The sign test is an alternative to the 2nd derivitive test for determining if a critical point is a relative maximum or a relative minimum.

To find maxima, you take the first derivitive of your function. Then you find where the derivitive is equal to 0 to get your critical points.
Once you have the critical points you can split the number line into intervals with endpoints at the critical points. Then take test values within each interval to determine the sign of the slope in that interval. If a critical point has a negative slope to the left and a positive slope to the right, the point is a relative minimum. if it is positive to the left and negative to the right, it is a relative maximum. If the signs on both sides are the same, it is not a relative maxima.