3. WHEN DO WE USE IT?
•When we compare the means of two
independent groups
•When the data are normally distributed,
Sk=0 and Ku=0.265
•When data are expressed in interval and
ratio
•When the sample is less than 30
6. EXAMPLE 1
The following are the scores in spelling of
10 male and 10 female AB students. Test
the null hypothesis that there is no
significant difference between the
performance of male and female AB
students in spelling. Use the t-test at .05
level of significance.
17. VI. CONCLUSION
Since the t-computed value of 2.88 is greater than
the t-tabular value of 2.101 at .05 level of
significance with 18 degrees of freedom, the null
hypothesis is disconfirmed. This means that there is
a significant difference between the performance of
the male and the female AB students in spelling
implying that the male students performed better
than the female students considering that the mean
score of the male student of 13.1 is greater
compared to the average score of female students of
18. EXAMPLE 2
Two groups of experimental rats were
injected with a tranquilizer at 1.0 mg and
1.5 mg dose respectively. The time given
in seconds that look them fall asleep is
hereby given. At .01 level of significance,
test the null hypothesis that the difference
in dosage has no effect on the length of
time it took to them to fall asleep.
29. VI. CONCLUSION
Since the t-computed value of -0.40 is
within the critical value of -2.878 at
.01 level of significance with 18
degrees of freedom, the null
hypothesis is confirmed. This means
that no significant difference was
bought about by the dosages on the
30.
31.
32. EXAMPLE 1
The mean score in spelling of 10 males is
13.1 and standard deviation 4.108, while
10 females have a mean score of 7.8 and
standard deviation 3.795 . Test the null
hypothesis that there is no significant
difference between the performance of
male and female AB students in spelling.
Use the t-test at .05 level of significance.
36. EXAMPLE 2
Two groups of experimental rats were
injected with a tranquilizer at 1.0 mg have
the average time of 10.79 seconds and
standard deviation of 1.684, and 1.5 mg
have the average time of 11.11 seconds and
standard deviation of 1.928. 11 rats were
injected by 1.0 mg and 9 rats by 1.5 mg. At
.01 level of significance, test the null
hypothesis that the difference in dosage has
no effect on the length of time it took to
41. 1. A Math teacher wants to compare the male
and female in his, if they performed
differently on the tests he gave last semester.
The scores of male and female is hereby
given. Use the t-test for two independent
samples at .05 level of significance to test the
null hypothesis that there is no significant
difference in the performance of Class A and
Class B in the test given last semester.
Male 13.3, 6.0, 20.0, 8.0, 14.0, 19.0, 18.0, 25.0,
16.0, 24.0, 15.0, 1.0, 15.0
Female 22.0, 16.0, 21.7, 21.0, 30.0, 26.0, 12.0,
23.2, 28.0, 23.0
42. 2. A statistic teacher wants to compare his
two classes to see if they performed any
differently on the tests he gave. Class A
had 15 students with an average score of
70, standard deviation 15. Class B had 14
students with an average score of 74,
standard deviation 25. Using alpha .05,
did these two classes perform differently
on the tests?
