This version is built to force actual work. Many prompts now require computing sample size, response rate, nonresponse rate, subgroup percentages, treatment counts, and significance-style reasoning from numbers instead of just naming a term.
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Population, sample, sample size, response rate
Compute the numbers first, then connect them to the right ideas.
12 questions
Population, sample, sample size, response rate
Compute the numbers first, then connect them to the right ideas.
Core ideas
- The population is the full group you want information about.
- The sample is the group from which data were actually collected.
- Sample size counts actual responses or observations, not just people contacted.
- Response rate = responses ÷ attempted contacts × 100.
- Nonresponse rate = 100 − response rate.
Useful formulas
- Response rate = responses / contacted × 100
- Nonresponse rate = nonresponses / contacted × 100
- Subgroup percent = subgroup / total × 100
Question 1 — Sample size
A university emails 240 off-campus students and 78 respond. Enter the sample size.
Question 2 — Response rate
Using the same survey, enter the response rate as a percentage rounded to one decimal, without the percent sign.
Question 3 — Nonresponse rate
Using that same survey, enter the nonresponse rate as a percentage rounded to one decimal, without the percent sign.
Question 4 — Actual nonresponses
How many students did not respond? Enter only the number.
Question 5 — Physician response rate
A survey is sent to 100000 physicians and 2379 respond. Enter the response rate as a percentage rounded to two decimals, without the percent sign.
Question 6 — Physician nonresponse rate
Using that physician survey, enter the nonresponse rate as a percentage rounded to two decimals, without the percent sign.
Question 7 — Greenville age share
A sample contains 436 adults age 18–64 and 253 adults age 65 or older. Enter the percent of the sample age 18–64, rounded to two decimals, without the percent sign.
Question 8 — Greenville senior share
Using the same age counts, enter the percent of the sample age 65 or older, rounded to two decimals, without the percent sign.
Question 9 — Favorite category share
In a survey of 560 students, 165 choose category A. Enter the percentage choosing category A, rounded to one decimal, without the percent sign.
Question 10 — County survey response rate
A county mails 1250 tax questionnaires and receives 965 back. Enter the response rate as a percentage rounded to one decimal, without the percent sign.
Question 11 — County survey nonresponses
Using that county survey, how many questionnaires were not returned? Enter only the number.
Question 12 — Sample size from completed forms
A pollster sends 900 surveys, 812 are opened, but only 604 are completed fully. For the final analysis, enter the sample size.
Bias, sampling distortion, and comparison calculations
Quantify what the sample is saying, then decide whether the design deserves trust.
10 questions
Bias, sampling distortion, and comparison calculations
Quantify what the sample is saying, then decide whether the design deserves trust.
Core ideas
- Bias comes from the method, not just the sample size.
- Voluntary response samples often exaggerate strong opinions.
- Coverage problems can systematically miss important groups.
- A percentage can be numerically correct for the sample but still misleading for the population.
Question 13 — Honors seminar estimate
Five students in an honors psychology seminar are asked whether they would pay dues to join a new club, and 4 say yes. Enter the sample percentage saying yes, without the percent sign.
Question 14 — Direction of likely bias
Using that 80% estimate from honors students, type overestimate or underestimate for the likely bias direction if the target is all psychology majors.
Question 15 — Landline coverage gap
A city adult population is 62% age 18–64, but a landline-only sample is 48% age 18–64. Enter the size of the undercoverage gap in percentage points.
Question 16 — Voluntary web poll share
An online voluntary poll gets 240000 votes, and 156000 favor option A. Enter the sample percentage favoring option A, without the percent sign.
Question 17 — Why that 65% still may fail
Type the two-word design flaw for that web poll.
Question 18 — Gym estimate
A gym surveys 90 people leaving the weight room, and 72 say they exercise at least four times per week. Enter the sample percentage, without the percent sign.
Question 19 — Bias direction from gym sample
If the target is all adults in town, type overestimate or underestimate for the likely direction of that 80% result.
Question 20 — Difference in sample versus population
A biased sample estimate is 80%, but a stronger citywide benchmark is 54%. Enter the difference in percentage points.
Question 21 — Nonresponse comparison
Survey A has a 22.5% response rate. Survey B has a 61.0% response rate. Enter how many percentage points higher Survey B’s response rate is.
Question 22 — Missing cases
A survey contacts 3200 adults and obtains 704 completed responses. How many did not complete the survey? Enter only the number.
Question wording, variables, and subgroup percentages
Mix calculation with the logic of what the data are trying to measure.
10 questions
Question wording, variables, and subgroup percentages
Mix calculation with the logic of what the data are trying to measure.
Core ideas
- Wording can be clear or unclear and neutral or slanted.
- The explanatory variable is the possible driver.
- The response variable is the measured outcome.
- Subgroup percentages often reveal imbalance or a misleading frame.
Question 23 — Loaded wording classification
A survey asks: “Given the growing threats from climate change, should we reduce our dependence on fossil fuels?” Type exactly one answer: clear and slanted, clear and neutral, unclear and slanted, or unclear and neutral.
Question 24 — Insurance wording classification
A question says a policy would “insure everyone and reduce administrative costs” before asking whether it should be adopted. Type exactly one answer: clear and slanted, clear and neutral, unclear and slanted, or unclear and neutral.
Question 25 — Technical overload classification
A dense question uses jargon and loaded assumptions before asking for support. Type exactly one answer: clear and slanted, clear and neutral, unclear and slanted, or unclear and neutral.
Question 26 — Explanatory variable
A study compares level of education with the rate of motor vehicle crash deaths. Type the explanatory variable.
Question 27 — Response variable
In that same study, type the response variable.
Question 28 — Lurking variable label
If vehicle age and safety features are not the main study variables but still affect the relationship, type the correct label: lurking, response, or sampling.
Question 29 — Study-hours subgroup
In a class, 84 of 140 students study at least 8 hours per week. Enter the percentage, rounded to one decimal, without the percent sign.
Question 30 — Test pass share
In that same class, 98 of 140 students pass the test. Enter the pass rate, rounded to one decimal, without the percent sign.
Question 31 — Percentage-point difference
Using the last two percentages, enter the difference in percentage points between the pass rate and the 8-plus-hours study rate.
Question 32 — Lurking-variable reasoning
Type yes or no: Prior preparation could still distort the relationship between study-hours and test scores.
Observational studies, experiments, treatments, and significance
Count the design pieces and use the numbers to interpret results.
10 questions
Observational studies, experiments, treatments, and significance
Count the design pieces and use the numbers to interpret results.
Core ideas
- An observational study measures without imposing treatment.
- An experiment imposes a treatment or randomly assigns conditions.
- For multiple factors, treatments are combinations of levels.
- Statistical significance means a difference that large would be unlikely from chance alone.
Useful formulas
- Number of treatments = multiply the number of levels across factors
- Group rate = successes / group total × 100
- Difference in rates = group 1 rate − group 2 rate
Question 33 — Study type
Researchers compare shoppers at stores with more creative windows versus less creative windows without randomly assigning shoppers. Type observational or experiment.
Question 34 — Creative-window entry rate
At stores with creative windows, 112 of 280 shoppers entered the store. Enter the entry rate as a percentage, without the percent sign.
Question 35 — Less-creative entry rate
At stores with less creative windows, 70 of 280 shoppers entered. Enter the entry rate as a percentage, without the percent sign.
Question 36 — Difference in entry rates
Using those two groups, enter the difference in entry rates in percentage points.
Question 37 — Why causation still fails
Type the key issue in one word: Since this was not a randomized experiment, outside differences may create ______.
Question 38 — Treatment count
An experiment has 2 factors. Factor A has 3 levels and Factor B has 4 levels. How many treatments are there? Enter only the number.
Question 39 — Equal assignment per treatment
A completely randomized experiment has 96 subjects and 3 treatments with equal group sizes. How many subjects per treatment? Enter only the number.
Question 40 — Larger difference
In a drug experiment, 18 of 60 in the treatment group improve and 9 of 60 in the control group improve. Enter the difference in improvement rates in percentage points.
Question 41 — Statistical significance meaning
Type rare or common: If that observed difference is statistically significant, a difference that large would be relatively ______ from chance alone.
Question 42 — Experiment versus observational
Participants are randomly assigned either to a supplement or to an inactive pill. Type observational or experiment.