Pleeese hep if you have a test average of 92 and a standard deviation of 1.8, you generally do well on tests.
t f

Yes, that's true PROVIDED your test scores are normally distributed.

If they are, then more than 99% of your test scores are within three
standard deviations of the mean. 

You told us that 3-sigma = 5.4 .  So less than one score out of every
hundred tests you take is lower than  86.6  or higher than  97.4 . 

You are remarkably consistent, so I guess Jupiter must have been
in its ascendancy next door to the house of Andromeda about an
hour before you were born, or some such nonsense.

What the heck don’t understand