HS305 Unit 8 Sampling and Measurement Plan Example

Course	HS305 Research Methods for Health Sciences
Unit	Unit 8
Paper type	Sampling and measurement plan
Length	About 1,100 words, 6 pages double-spaced
Format	APA 7 student paper
School	Purdue University Global
Program	BS in Health Science
Updated	October 2026

Free sample paper for HS305 Unit 8

Who May Enter and How Back Pain Becomes a Number: A Unit 8 Sampling and Measurement Plan for a Sit-Stand Desk Trial

[Student Name]

Purdue University Global

HS305: Research Methods for Health Sciences

Unit 8 Sampling and Measurement Plan

[Instructor Name]

[Date]

The two employers, the recruitment figures and the assumed standard deviation are composite; the instruments, their validation studies and the change thresholds cited are real.

What this part is doingNaming the three questions in the lead tells the grader the plan is organized around decisions, not around a list of methods vocabulary.

Population

The target population is adults whose jobs keep them seated at a desk for thirty or more hours each week and who have recurring low back pain. That is the group the findings are meant to describe. The accessible population is narrower: salaried and hourly office staff at two regional employers, a [1,400]-person insurance claims center and a [900]-person county administration building, both within one metropolitan area. The difference between the two populations matters, because a result found among claims processors and county clerks will carry over to desk workers in general only as far as those workplaces resemble others. Both employers use open-plan floors with assigned desks, so the plan cannot speak to hot-desking offices or people who work mainly from home, and the final report will say so.

Eligibility

Each criterion is written as a test with a threshold, so two research assistants screening the same person would reach the same answer.

Inclusion criteria:

1. Age 18 to 65 years on the day of screening.

2. Rostered for 30 or more weekly hours at an assigned desk, confirmed by the employer's roster.

3. Low back pain on at least half the days of the past four weeks, by self-report on the screening form.

4. Average low back pain intensity over the past week rated 3 or higher out of 10 on a numeric rating scale.

Exclusion criteria:

1. Current use of any height-adjustable desk or desktop converter at work.

2. Spinal surgery within the past twelve months.

3. Pregnancy, or planned pregnancy during the study period.

4. A diagnosed cause of back pain that needs other care, such as a fracture, infection or nerve root compression with leg weakness, identified on the screening checklist.

5. A planned leave of more than two weeks during the twelve-week study.

The fourth inclusion criterion sets a floor so that participants have enough pain for a meaningful drop to be possible. Someone who rates their usual pain at 1 cannot improve by two points.

How Participants Are Found

Recruitment is by volunteer response. Each employer's human resources office will send one study email and post one notice on its intranet, and interested staff will complete an online screening form. This is a convenience sample: the staff who reply probably differ from colleagues who ignore the email, for instance in having worse pain or more interest in desk equipment. The plan accepts that limit and records it. Screening will log how many people opened the form, how many were eligible and how many enrolled, so readers can judge how selected the sample is.

Random assignment happens only after someone has enrolled, and it makes the two desk groups comparable with each other; it does nothing to make the volunteers representative of desk workers in general.

What this part is doingSeparating finding participants from assigning them is the distinction most plans in this unit blur, so the highlighted sentence states it outright.

How Participants Are Assigned

Enrolled participants will be allocated in a 1 to 1 ratio to a sit-stand desk or to continue with their standard fixed desk. Allocation will use a computer-generated list in random blocks of four and six, stratified by employer, held by a statistician who has no contact with participants. Because coworkers sharing a floor might talk about their desks, allocation by floor was considered; it was set aside because it would need many more participants to reach the same power.

Sample Size

The primary comparison is the difference in mean pain intensity between groups at twelve weeks. Changes of about two points on the 0 to 10 scale, or about 30 percent, are commonly treated as the smallest improvement that matters to people with back pain (Ostelo et al., 2008). Assuming a standard deviation of [2.5] points, 80 percent power and two-tailed testing at the 0.05 level, detecting a two-point difference needs about [25] participants per group. Allowing for [20] percent loss by week twelve brings the target to [32] per group, or [64] in total. Those inputs are written in brackets because the standard deviation is borrowed from earlier workplace samples and will be checked against the first [20] baseline scores.

Measures

Primary outcome: low back pain intensity, which participants rate as their average over the past week on a numeric scale anchored at 0 for no pain and 10 for the worst pain imaginable. The scale is quick, widely used and responsive to change in people with low back pain (Childs et al., 2005). It is collected at baseline, week six and week twelve.

Secondary outcome: disability from back pain on the Oswestry Disability Index, ten items on everyday activities such as sitting, standing, lifting and sleeping, scored from 0 to 100 percent. Its reliability and validity have been reviewed across many populations (Fairbank & Pynsent, 2000). It is collected at the same three points.

Process measure: time spent sitting during work hours, recorded by a thigh-worn activity monitor for five working days at baseline and at week twelve. A thigh-worn device can tell sitting from standing by the angle of the leg, which a wrist or hip device cannot do reliably, and its field use with adults has published guidance on wear and processing (Edwardson et al., 2017). This measure shows whether people actually stood more. If pain falls but sitting does not change, the desk is unlikely to be the reason.

What this part is doingA process measure is what lets the final report say whether the desk was used, which turns a null result into something interpretable.

Background measures: age, sex, job role, hours at the desk, years in a desk job and pain duration, collected once at baseline to describe the sample and to check that the groups are balanced.

Threats to the Plan and the Steps Taken

Self-report. Pain is reported by participants who know which desk they have, and those with the new desk may expect to feel better. The plan cannot remove this, but the activity monitor gives one outcome that does not rely on self-report.

No blinding. Neither participants nor their supervisors can be blinded. The person entering data and the statistician will work from coded group labels until the analysis is final.

Dropout. People may leave their jobs or stop answering surveys. The plan sends a reminder after three days, keeps the follow-up form under five minutes, and analyzes everyone in the group they were assigned to, whether or not they used the desk as intended.

References

Childs, J. D., Piva, S. R., & Fritz, J. M. (2005). Responsiveness of the numeric pain rating scale in patients with low back pain. Spine, 30(11), 1331-1334. https://doi.org/10.1097/01.brs.0000164099.92112.29

Edwardson, C. L., Winkler, E. A. H., Bodicoat, D. H., Yates, T., Davies, M. J., Dunstan, D. W., & Healy, G. N. (2017). Considerations when using the activPAL monitor in field-based research with adult populations. Journal of Sport and Health Science, 6(2), 162-178. https://doi.org/10.1016/j.jshs.2016.02.002

Fairbank, J. C. T., & Pynsent, P. B. (2000). The Oswestry Disability Index. Spine, 25(22), 2940-2953. https://doi.org/10.1097/00007632-200011150-00017

Ostelo, R. W. J. G., Deyo, R. A., Stratford, P., Waddell, G., Croft, P., Von Korff, M., Bouter, L. M., & de Vet, H. C. (2008). Interpreting change scores for pain and functional status in low back pain: Towards international consensus regarding minimal important change. Spine, 33(1), 90-94. https://doi.org/10.1097/BRS.0b013e31815e3a10

Reading the HS 305 Unit 8 instructions

Unit 8 usually asks you to describe who would be studied and how the main variables would be measured, building on the question and design from earlier units. Plans often run three to four pages under headings for population, eligibility, sampling, sample size and measures. Instructors look for criteria precise enough that two people would screen the same way, a named sampling method with its limits admitted, and instruments identified by name, scale and timing with evidence of reliability or validity. Many sections want a justified sample size, sometimes with a simple calculation. A short section on threats to the plan, with the step taken against each, frequently earns credit. Cite the instruments' validation studies rather than describing scales from memory.

How the HS 305 Unit 8 example is put together

The population section distinguishes the desk workers the findings should describe from the staff of two composite employers who can actually be reached, and names what that gap costs. Eligibility follows as numbered inclusion and exclusion criteria, each a test, with a note on why a pain floor is needed. Recruitment by email and intranet is labeled a convenience sample, and the highlighted sentence separates random assignment from representativeness. Allocation in stratified random blocks is explained, including why allocation by floor was rejected. The sample size paragraph walks from a published meaningful change to a bracketed target. Three measures follow with scale, timing and a supporting study, plus background variables. A closing section pairs self-report, the absence of blinding and dropout with the step taken against each.

HS305 Unit 8 rubric: what earns full points

Sampling and measurement plans tend to be graded on precision of eligibility criteria, appropriateness of the sampling approach, justification of sample size, quality of measures and recognition of limits. Eligibility and measures generally carry the most points, because they are where vague plans fail: a criterion such as office workers with back pain cannot be applied consistently, and a measure without a named instrument cannot be evaluated. Sampling credit rewards naming the method and admitting what it cannot support. Sample size points depend on a stated basis rather than a round number. Recognizing limits earns credit when each is paired with a concrete step. Accurate citations for every instrument complete the expectations.

HS305 Unit 8 help: mistakes that cost points

A common gap is eligibility written as description, such as adults with back pain, with no threshold or time window. Another is treating random assignment as if it made a volunteer sample representative. Some students name an outcome, such as pain, without naming the instrument, its scale or when it will be collected. Others choose a sample size with no reasoning or copy one from an unrelated study. Leaving out a process measure means a null result cannot be interpreted. If your question uses a different population or outcome, perhaps nurses on night shift or a sleep measure, send your Unit 4 question and design and we can help you write criteria and measures that hold up.

Get an HS305 Unit 8 example written to your instructions

The question carried over from earlier units is where a Unit 8 plan begins, so it travels with the instructions and the rubric. Eligibility and recruitment are set out, sampling is kept apart from assignment, and each measure arrives with its evidence and timing. Completed in 24-48h; no fee on a first custom sample. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.

More HS305 papers and BS in Health Science samples

HS305 Unit 8 questions, answered

What is the difference between random sampling and random assignment?

Random sampling decides who gets into the study and supports generalizing to the population sampled. Random assignment decides which group each participant joins and supports causal conclusions within the study. A plan can have either, both or neither. The sample plan uses assignment without sampling, and it says so, which is the distinction many HS305 graders test in this unit.

Does an undergraduate plan need a power calculation?

Many sections ask for a justified target rather than a full calculation, and some accept a rationale based on similar published studies. Where a calculation is expected, the inputs matter more than the arithmetic: the difference worth detecting, the variability and the accepted error rates. The sample shows those inputs in brackets so the reasoning shows even though the study is composite.

Can I create my own questionnaire for the outcome?

It is possible but costly, because a new instrument has no evidence of reliability or validity until someone tests it. Using an established scale with published evidence is the stronger choice for most undergraduate plans. If your question requires a new measure, the plan should say how it would be piloted and checked before the main study begins.

Where can I find a free HS305 Unit 8 sample paper?

You can read the full Unit 8 sampling and measurement plan here, covering eligibility, recruitment, sample size and three measures for a sit-stand desk trial.

Why include a measure of sitting time when the outcome is pain?

It shows whether participants actually stood more. If pain changed but sitting did not, the desk is unlikely to be the reason, and if neither changed, the plan can tell nonuse from no effect.