Which of the following conditions must be met in order to make a statistical inference about a population based on a sample if the sample does not come from a normally distributed population?
a. Mu greater-than-or-equal-to 30
b. x Overbar greater-than-or-equal-to 30
c. n greater-than-or-equal-to 30
d. Upper N greater-than-or-equal-to 30