In: Statistics and Probability
A company manager wishes to test a union leader's claim that absences occur on the different week days with the same frequencies. Test this claim at the 0.05 level of significance if the following sample data have been compiled.
Day | Mon | Tues | Wed | Thurs | Fri |
Absences | 37 | 15 | 12 | 23 | 43 |
= proportion of total absence on weekdays occurring on
Monday.
= proportion of total absence on weekdays occurring on
Tuesday.
= proportion of total absence on weekdays occurring on
Wednesday.
= proportion of total absence on weekdays occurring on
Thursday.
= proportion of total absence on weekdays occurring on
Friday.
To test,
versus
the value of at least one of the
is different from
.
Now, observed frequencies =
= (37, 15, 12, 23, 43). Total frequency =
= 37+15+12+23+43 = 130.
Now, expected frequencies =
= (130 * 0.2, 130 * 0.2, 130 * 0.2, 130 * 0.2, 130 * 0.2) = (26,
26, 26, 26, 26).
Test statistic =
=
= 28.30769.
Now, k = 5 = no. of weekdays. Critical value =
.
Since, the test statistic is greater than the critical value, we
reject
. We conclude that there is enough evidence to reject the claim
that absences occur on different week days with the same
frequencies.