The document discusses a group project analyzing resting heart rate as a process. The group measured heart rates using a smartwatch over multiple days. They identified heart rate as a variable, critical characteristic for determining heart health. An X-bar R control chart was used for analysis since the subgroup size was 4. Some points were found to be out of control, usually when the person was working on stressful projects or assignments. Overall, the process capability analysis indicated the need for improvement since the process was not stable or centered.

1. ISE 508: Quality Assurance
Mini-Project 5: Process Control
Group 18
Group Members :
• Mourya Busareddy-50315878 – Working in Minitab and Excel, Brainstorming about project ideas.
• Nilashish Singha-50320680 – Working in Minitab and Excel, Brainstorming about project ideas.
• Pearldeep Dhingra-50321627 – Data Collection, Brainstorming about project ideas.
• Pran Chaliha-50315094 – Analyzing Important Characteristics of the Process, Brainstorming about project ideas.
• Saipreeti Vasan-50314941 – Analyzing Important Characteristics of the Process, Brainstorming about project ideas.
Interpretation of the results and the answering the question was a collective effort by the team.

2. Question 1:
For this study we looked at different processes from our daily life but most of the processes are
random, not stable and not repetitive in nature. In this wake of lockdown, most of us have limited
physical activity and have developed eating habits that affect not only our physical health but also
the health of our heart. Thus, it is important to regulate and assess the “Healthy heart” from time
to time in order to determine any heart conditions that can take a serious toll on our body in the
long term. In determining the Healthy heart, we need to check the blood pressure, heart rate and
perform some blood tests. One easy and quick process is to check the Resting Heart Rate. To do
so we used a smartwatch which has a special in-built app - “Cardiogram”.
Reasons why we chose Resting Heart Rate operation:
• Heart rate just like blood pressure is an important and quick way to examine a person’s health.
• Availability of equipment like smartwatch and supporting mobile applications to collect
accurate data.
• Helps us to judge the strength of your blood flow and blood pressure in different areas of your
body.
• Resting Heart Rate is repetitive and naturally occurring throughout the day, hence good for
control chart analysis.
If the heart rate is not checked properly it will negatively affect the process of checking Healthy
heart giving misleading results.

3. Question 2:
Usually, the normal adult resting heart rate is between 60 to 100 BPM. When it drops below or
above the range specified it becomes a matter of concern. If you are exercising, or performing any
kind of activity, or anxious, stressed then your heart will beat faster, that is it might be above 100
BPM. Athletes and people who are highly active might have heart rate below 60 BPM or when a
person is asleep it drops till 40 or 50 BPM which is normal but when it drops further till 30 or 20
it can be dangerous. We can say that resting heart rate is a critical characteristic and cite reasons
below:
• A resting heart rate below 30 BPM can cause Bradycardia where the heart doesn’t pump
enough blood which can be fatal if not taken care off. If the resting heart rate observed is not
within the range specified even though there is no physical activity, or the body is at rest then
it can cause major heart problems.
• Similarly, if the resting heart rate observed is beyond 110 BPM it results in a condition known
as tachycardia which happens when the electrical signals in the organ's upper chambers misfire
and cause the heart rate to speed up. It beats so fast that it can't fill with blood before it
contracts. When such a condition is observed despite at rest it can prove out to be fatal.
Note: Our critical characteristic is not the heart rate sensor as we are not considering the
measurement system as our main subject of study. Main process is to assess the healthy heart and
heart rate is one of the critical parameters in determining the condition of the heart.

4. Question 3:
We identified Heart rate is of variable data type. The smartwatch records the data every hour which
gives a numerical output in Beats per minute. Since, the data recorded is continuous in nature we
can say it is a variable output and not attribute.
As we want to determine the condition of the healthy heart which means it has to be in the range
of 60-100 BPM (Resting). Therefore, the specification limits of our characteristic will be 60 (lower
limit) and 100 (upper limit). Reference:-
https://www.health.harvard.edu/blog/resting-heart-rate-can-reflect-current-future-health-
201606179806
A healthy heart range observed is mostly between 60 to 100 BPM (Resting). But as we know
sometimes it can drop below or increase the range when performing certain tasks.

5. Question 4:
After data collection and analysis, we found that our data type was variable in nature. And since
we are dealing with Continuous data type we next proceeded with sub group size determination.
When subgroup size i.e; n = 1, the type of control chart applicable is X-MR/I-MR chart, if 2<n<9,
the feasible control chart for analyzing is X-bar R chart and finally if n >= 10 then one goes for X-
bar S Charts as it is then the most applicable control chart.
X-bar S chart is used when we are particularly concerned about the dispersion of the process, it
might be that the R chart is not sufficiently precise and in such case an X-bar R chart comes useful.
Standard deviation (s) charts are used where variation in a process is small. But in our case we
found our process variation to be quite significant. Therefore, X-bar S chart won’t give us the best
analysis for our data.
CUSUM charts are another type of control chart which simply add up the deviations from each
data point to the mean or target, these are acutely effective at detecting small shifts.
But in our context, we found the shift in the data points are significantly large to consider the
CUSUM type control chart.
Therefore, taking all the above-mentioned points into consideration and based on the subgroup
categorization (in our case n = 4) we can be certain that X-bar R chart will be the most appropriate
in our case with the current set of data for most appropriate analysis and examining the process
stability.
Also, Heart rate for any individual needs to be stable and lying with the limits. As stability is one
of the prime essentials of this type of measurement , using the X bar R charts is more sensible.
Another advantage of using X-bar and R charts is to analyze the results of process improvements.
Here we would consider how the process is running during an activity and compare it to how it
ran before an activity . So , the changes in activities could be validated using these charts.

6. Question 5:
We collected the data after every hour for 9 hours for 4 days. At each hour we collected 4 sample
points, so we have taken subgroup size as 4 in our study.
During the initial phase one value is out of control, the team has to perform the root cause analysis
for the special causes. We are only considering the points that are above 100 BPM only. We
identify that the following points are out of control:
14th and 15th point- Sudden change in levels. From the below table we can see that the person
was working on a project and later went in the kitchen to cook food. A sudden drop is observed as
a result of switching from a strenuous to a relaxing environment.
21, 22, 23, 24th point - successive data points above the central line. Here the person was subjected
to a lot of stress while working on the project since it was due at that time.
29th point- Heart rate significantly increased as the person was working on an assignment.

7. The test failed at the following points:
Points Date Time
Mean
BPM Activity
Within Specification
Limit (60-100)
2 4/30/2020 2:30 100 Assignment Yes
8 4/30/2020 8:30 81.5 Watching Movie Yes
9 4/30/2020 9:30 69.25 Sleeping Yes
14 5/1/2020 5:30 104.25
Working on a
Project No
15 5/1/2020 6:30 74 working in kitchen Yes
18 5/1/2020 9:30 68.25 Sleeping Yes
20 5/2/2020 2:30 79 Kitchen Yes
21 5/2/2020 3:30 101.75 Working on project No
22 5/2/2020 4:30 106.25 Working on project No
23 5/2/2020 5:30 113.5 Working on project No
24 5/2/2020 6:30 112 Working on project No
27 5/2/2020 9:30 82.75 Sleeping Yes
29 5/3/2020 1:30 103.75
Working on
assignment No
35 5/3/2020 8:30 82.75 watching movie Yes
36 5/3/2020 9:30 67.5 sleeping Yes
We used the Capability analysis to find the Process Capability of the process. Considering the
normal distribution with LSL to be 60; USL to be 100 and sub group of 4.
On comparing the solid overall curve and the dashed within curve to see how closely they are
aligned. We could see a substantial difference between the curves indicating that the process is not
stable or that there is a significant amount of variation between the subgroups.

8. Since our process is not a standard manufacturing process , we could see a Lower Cpk value
indicating that our process needs improvement . The difference in Cp and Cpk indicates that the
process is not centered . We could also see this from the Pp and Ppk values which is a reflection
of overall process capability . The difference between Ppk and Cpk represents the improvement in
process capability that we could expect if shifts and drifts in the process were eliminated.
To conclude the analysis, we can say that most of the average points going above 100 (upper
specification limit) are when the person under consideration is working on the projects and
assignments with tight deadlines.