Option c) 0
In Z distribution the mean is always 0 because the maximum value is + infinity and the minimum value is always - infinity
so means = (+infinity + (-infinity))/2
=(+infinity -infinity)/2
=0/2
=0
In Z distribution the mean is always 0 because the maximum value is + infinity and the minimum value is always - infinity
so means = (+infinity + (-infinity))/2
=(+infinity -infinity)/2
=0/2
=0