|
Example A group of 200 students have the
mean height of 154 cms. Another group of 300 students have the mean
height of 152 cms. Can these be from the same population with S.D.
of 5 cms?
Solution: Ho : m1
= m2, the samples are from
the same population.
Ha : m1
¹ m2, here
= 154 cms, 
= 152 cms, s = 5 cms, n1 = 200 and n2
= 300.
Now, 
i.e. the z-score is highly significant. Therefore, we reject Ho i.e. it is not likely that the two samples are from the same population.
Example Random samples from two population
gave the following results :
| |
Population A |
Population B |
|
Mean |
490 |
500 |
|
S.D. |
50 |
40 |
|
Size |
300 |
300
|
Is the difference between the means significant?
Solution: Ho : m1
= m2,
the difference between the two means is not significant. i.e. Ha
: m1
¹ m2.
We have  = 490, = 500, s1 = 50, s2 = 40, n1 = 300 and n2 = 300.
Therefore, the null hypothesis Ho is accepted i.e. the difference between the two means is not significant.
|
