Why census a 2,940-household list, what margin 159 eligible adults support, and who stays invisible: MT355's Unit 7 sampling plan for a school weighing adult classes. Searches like "mt 355 unit 7 assignment example", "mt355 unit 7 sample" and "mt355 unit 7 example" land here.
What a finished MT355 Unit 7 sampling plan looks like
Five pages with two calculation boxes and a coverage table. Population and frame are defined separately: adults within fifteen minutes of North or Riverside who cannot swim a length, against the school's list of 2,940 current and recent family households, 1,710 near North and 1,230 near Riverside. Box one sizes the need: a 5-point margin at 95 percent confidence requires 385 eligible respondents, which at 24 percent response and 22.5 percent incidence means 7,130 invitations, more than twice the list. So the plan invites every household and expects about 159 eligible completes, a margin near 7.8 points. Box two sets a panel quota of 250 eligible adults across 14 ZIP codes, reported without any margin. The coverage table lists four groups the design misses.
How a MT355 Unit 7 example is structured
Target and frame are defined first, since the gap between the adults the owner wants and the lists the school actually holds shapes everything after. The size calculation follows, shown step by step with its three inputs, confidence, margin and assumed proportion, and with response rate and incidence sourced from an earlier school survey and the Unit 5 soft launch. The calculation's verdict drives the design: when a list cannot supply the target, sampling from it only shrinks the yield further, so a census is the rational choice. The panel supplement is justified by coverage rather than precision, reaching adults with no child at the school, and the plan says plainly that opt-in panel results carry no margin of error. Coverage gaps close the plan, each paired with the direction it would likely bend the results.
Two definitions, kept apart
Target: adults near either pool who cannot swim one length. Frame: 2,940 family households on the school's list. Everyone without a child enrolled sits between the two.
385 needed, 159 available
A 5-point margin needs 385 eligible respondents. At 24 percent response and 22.5 percent incidence, that means 7,130 invitations, far beyond a list of 2,940.
Why every household is invited
Drawing a sample from a list already too small would cut the yield further. The whole list is surveyed, and the plan accepts a margin near 7.8 points.
A panel for coverage, not precision
250 eligible adults from an online panel in 14 ZIP codes reach people with no link to the school. Their answers are reported without a margin.
Adults no list reaches
Non-English speakers, adults offline, people avoiding any swim-related survey, and adults far from either pool. For each gap, the likely direction of bias is stated.
Where marks go in MT355 Unit 7
Honesty about the frame carries the heaviest weight, so a plan quoting a sample size without naming the list it comes from skips the check graders make first. A size figure that omits its confidence level, its margin or its assumed proportion cannot be checked, and graders treat it as a guess. Invitation counts that ignore response rate and incidence leave a plan hundreds of respondents short. Attaching a margin of error to opt-in panel results is a common and costly error. Coverage gaps listed generically, time and budget, earn far less than gaps tied to this design, such as adults without children at the school. A plan claiming the results will represent all local adults, when the frame holds only families, draws a firm deduction in most sections.
Get a MT355 Unit 7 example written to your instructions
Describe the frame your Unit 7 case offers, imperfect or not, and send it with the prompt and rubric. The plan comes back inside 24-48h with the size calculation shown step by step, the frame's limits argued, and the uncovered groups named with the direction each would bend your results. Your first custom sample is free.
MT355 Unit 7 questions, answered
When is surveying an entire list better than sampling it?
When the list is too small to yield the respondents needed even if everyone is invited. Sampling from it would reduce the eligible count further and widen the margin. The MT355 sample shows the arithmetic: a 5-point margin would need 7,130 invitations from a list of 2,940. In that situation a census is the rational design, and the plan should say why.
Why can an online panel not have a margin of error?
A margin of error describes how far a random sample's estimate is likely to fall from the population value. Opt-in panel members choose to join, so there is no known probability of selection, and the formula's assumptions fail. Panels can still be useful for direction and comparison. The sample reports panel results separately and says plainly that no margin applies to them.
Where do the response rate and incidence figures come from?
From the best evidence available, stated with its source. The sample takes 24 percent response from the school's previous customer survey and 22.5 percent incidence from its own pilot, nine eligible respondents among forty. Both are assumptions, and the plan shows how the expected yield would change if either proved lower, so a reader can judge the risk.