Find the mean, median and mode of the data set. round to the nearest tenth.
77,78,96,90,99,89,81,79,82,79,76,98 ,77,84,92,78,70,69,82,89,95,89

Median is 82  Count in from both ends till you find a middle number or it is the number that is in between two numbers.
Mean is 79.2  Add them all up, and divide by how many numbers there are. I counted twenty numbers when I transferred them on my worksheet so double check my work. 
Mode is 89 This is the number(s) that appears the most often.

Please put the numbers in numeric order from least to greatest to ensure the most accurate answer. It is very difficult to re order this on to a worksheet.

Mean: 84.04
Median:82
Mode: 89

There are 22 numbers not 20!

Answer 20 centimeters15+8=2323-3=20so the answer is 20 centimeters