In: Statistics and Probability
A researcher wants to determine the impact that smoking has on resting heart rate. She randomly selects
77
people from
33
groups and obtains the heart rate data (beats per minute) in the table. Complete parts (a) through
(c).
Nonsmokers |
5050 |
5050 |
4848 |
6262 |
6767 |
5252 |
4747 |
|
|||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Light Smokers |
7272 |
6060 |
6565 |
6969 |
6363 |
7373 |
5959 |
||||||||||||||||
Heavy Smokers |
7171 |
8383 |
6363 |
7878 |
7575 |
7676 |
7676 |
(a) |
Test
the null hypothesis that the mean resting heart rate for each
category is the same at the
alpha equals 0.05α=0.05 level of significance. Note that the requirements for a one-way ANOVA are satisfied. |
Identify the null and alternative hypotheses.
A.
Upper H 0H0:
mu Subscript ns Baseline equals mu Subscript l s Baseline equals mu Subscript hsμns=μls=μhs
Upper H 1H1:
mu Subscript ns Baseline not equals mu Subscript l s Baseline not equals mu Subscript hsμns≠μls≠μhs
Solution:
a. The null and alternative hypotheses are:
We can use the excel ANOVA: Single Factor data analysis
tool to find the answer to the given questions.
The excel steps are:
Enter the data in excel.
Click on Data > Data Analysis > ANOVA: Single Factor > OK
Input Range: Select the data range for all the data including labels
Mark Labels in the first row
Alpha = 0.05
Choose the output range and click OK.
The output is given below:
Anova: Single Factor | ||||||
SUMMARY | ||||||
Groups | Count | Sum | Average | Variance | ||
Nonsmokers | 7 | 376 | 53.71428571 | 58.9047619 | ||
Light smokers | 7 | 461 | 65.85714286 | 31.47619048 | ||
Heavy Smokers | 7 | 522 | 74.57142857 | 38.95238095 | ||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Between Groups | 1536.285714 | 2 | 768.1428571 | 17.81774669 | 0.0001 | 3.554557146 |
Within Groups | 776 | 18 | 43.11111111 | |||
Total | 2312.285714 | 20 |
Since the p-value is less than the significance level, we, therefore, reject the null hypothesis and conclude that the mean resting heart rate for each category is not the same at the 0.05 significance level.