21 a)
range
1
57
A group of students were given a spelling test.
The table shows their marks.
Mark
b)
Frequency
students
6
5
c)
a) Work out the range of the marks.
mean
8.13
+
7
4
8
7
Submit Answer
b) How many students are in the group?
9
10
c) Work out the mean mark of the group.
10

Step-by-step explanation:

How many students are in the group? 7

8

step-by-step explanation:

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.