The feeling you did bad on a test but end up getting a good grade?

[joyce]

just took a math test today and im pretty confident i did good, but some girl said if you think you did bad you actually end up with a bad grade on the other hand where a person thinks they did bad actually ends up doing good...is this a myth or is this actually true? i believe if you did good u end up doing good while if u think u did bad there's a reason such as not knowing the questions..plz give me your opinions on this thanks guys