The mean heights of 3 groups of students consisting of 20, 16 and 14 students are 1.67m, 1.50m and 1.40m Respectively. What is the mean height of all the students?

Titilayo3491

9 years ago

wrong... 1.67+1.50+1.40/3=1.52

how did u gt 1.54 myschool

anon1909

5 days ago

Find total height for each group
Group 1: 20 * 1.67 = 33.4
Group 2: 16 * 1.50 = 24.0
Group 3: 14 * 1.40 = 19.6


Add up all heights and all students
Total height = 33.4 + 24.0 + 19.6 = 77.0
Total students = 20 + 16 + 14 = 50 students


Mean height = 77.0/50 = 1.54
Answer: 1.54 m


Why you can’t just do (1.67 + 1.50 + 1.40) / 3 = 1.52 m
That would only work if each group had the same number of students. Here group 1 is bigger and taller, so it pulls the overall average up.

Michaelimumoren

2 years ago

Both processes are technically correct.
but the one that gave 1.54 as answer is the most preferred calculation so the preferred answer is 1.54