On six tests you earn scores 89,81,85,82,89 and 89. what is your grade to the nearest whole number, and which measure of central tendency should you choose

You should use the Mean or avg as the central tendency. why? because you want to find the avg of the 6 scores. 

89 +81+85+ 82+ 89+ 89 = 515
515/ 6 = 85.833
or 86 when rounded to the nearest whole number