Mean, SD, t-test
Mon, Mar 8, 2027 · Week 8 · 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.
What a finished product looks like
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 it is unlikely to be due to chance alone.
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.
Also due today: Submit your statistics practice with calculations shown to the Schoology assignment by end of period.
WebXam problem for today's skill
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.