Explanation:
So basically To find the mean you have to add all the numbers and divide by how many numbers you have, but to do that you have to make sure the numbers are lined up correctly so
157,158,161,162,172 ( Correct Order ) Smallest to biggest now add these up
157 + 158 + 161 + 162 + 172 = 810 / 5 = 162
The mean height is 162 cm
The new mean height
Again we're going to do the same thing
157 + 158 + 161 + 162 + 169 + 172 = 979/6 = 163.16666 = 163 cm
Hence the first mean height is 162 cm and the new mean height is 162 cm