Question

The given table shows the scores of representative students of three sections in a Science exam.
A: 84 94 90 94
B: 74 94 84 84 97
C: 94 81 90
Is there a difference in the mean Science exam scores of the students from the three sections? Use a .05 level of significance.

Answer 1

Given:

A: 84 94 90 94

B: 74 94 84 84 97

C: 94 81 90

To find:

1) mean of section A = x1?

1) mean of section B = x2?

1) mean of section C = x3?

Step-by-step explanation:

The mean is that the sum of the values divided by the number of values.

∴ $\displaystyle X = \frac{Sum \ of \ the \ terms}{no \ of \ terms}$

1)

for section A:

mean x1 = $\frac{84+94+90+94}{4}$

           x1 = 90.5

2)

for section B:

mean x2 = $\frac{74+94+84+84+97}{5}$

        x2 = 86.6

3)

for section C:

mean x3 = $\frac{94+81+90}{3}$

          x3 = 88.33

The above data shows that there is a difference between the mean Science exam scores of the students from the three sections

Let ' d ' be the difference between sections.

1)

The Difference in the mean of section A & B :

d1 = x1 - x2

   = 90.5 - 86.6

d1 = 3.9

2)

The difference in the mean of section B & C :

d2 = x3 - x2

    = 88.33 - 86.6

d2 = 1.73

3)

The difference in the mean of section A & C :

d3 = x1 - x3

    = 90.5  - 88.33

d3 = 2.17