Mean, SD, t-test
Fri, Mar 5, 2027 · Week 7 · Biotechnology for Health (Biomedical Innovations)
Today's goal: Compute the mean and standard deviation and explain the purpose of a t-test for your data.
This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.
Using my baseline heart-rate data: 72, 70, 74, 71, 73 bpm.
Mean: (72 + 70 + 74 + 71 + 73) / 5 = 360 / 5 = 72 bpm.
Standard deviation (sample):
- Deviations from mean: 0, -2, +2, -1, +1
- Squared deviations: 0, 4, 4, 1, 1 (sum = 10)
- Divide by n - 1 = 4: 10 / 4 = 2.5
- Square root: SD = about 1.6 bpm
What a t-test compares: a t-test asks whether the difference between the means of two groups (my baseline mean vs my after-activity mean) is large enough, relative to the spread in the data, that a difference this big would be unlikely if the two conditions really made no difference.
Does my data call for one? Yes. I have two conditions (rest vs activity) and I want to know if the higher activity mean is a real difference, so a two-sample t-test fits.
This model shows the level of evidence and organization needed to complete: Completes the Problem 2 descriptive-statistics practice: mean and standard deviation computed per condition with steps shown, plus a written explanation of when a t-test is used.
- Name the variables and include units.
- Enter observations without changing the raw values.
- Check labels, calculations, and patterns before interpreting the data.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: Submit your statistics practice with calculations shown on Schoology by end of period.
Turn in: Statistics practice: mean, standard deviation, and t-test purpose
Go to Schoology to turn this in.
Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Claim ceiling: Today's evidence supports a classroom claim about today's lesson. It cannot prove causation, diagnose a real patient, or justify action outside this room.
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.
It builds this reusable test skill: Interpreting standard deviation as a measure of data spread.
- Name the concept or data pattern being tested.
- Cross out choices that violate that rule or the evidence.
- Justify the best remaining choice before checking the answer.