540 / 762
540
Chapter 12: Hypothesis Tests – Large Samples
insufficient sample evidence to claim that the average salary for the floor
managers is greater than $66,200 at the 5% level of significance.
Note:
Any difference between the sample mean and the postulated mean of
$66,200 may be due to chance.
(b) Left –tailed (one-tailed) Test
(where
is a specified proportion value)
T.S
:
̅
√ ⁄
or
̅
√ ⁄
for
unknown and
30
D.R
: For a specified significance level
, reject the null hypothesis
if the computed test statistic value
is less than -
.
Conclusion
: ……….
Note:
This is a left-tailed test because the direction of the inequality sign in
the alternative hypothesis is to the left.
Example 12-7:
A study was done on the media habits of American
children age 8 to 18 and found that these children are engaged with media on
average at least 6 hours per day. After reviewing much literature on the
subject, a university student hypothesizes that children in her state engage in
far less media than the reported 6 hours per day. Data on 100 randomly
selected children residing in her state yielded a mean of 5.8 hours/day and a
standard deviation of 1 hour/day. Test at the 5% level.
Summary information:
=100,
= 1.00 hour,
= 0.05,
̅
= 5.8 hour,
= 1.645, and
= 6 hours. Also,
√ ⁄
= 0.1 hour.
Click here for the Large Sample Test for a Single Population Mean Workbook