Statistics · Module 4
Answers and explanations · Ask who and what are missing
Compare these references after your own attempt. You can read them at any time; they do not record a live model or vendor run.
Statistics · Module 4
Compare these references after your own attempt. You can read them at any time; they do not record a live model or vendor run.
4A. Random assignment supports an intervention comparison among enrolled units under assumptions such as adherence, no interference and comparable outcome measurement. Volunteer recruitment from one shift limits population coverage. Differential dropout, spillover between groups or changing the measurement method for one group could compromise the comparison.
4B. Respondent mean=32/8=4.0. Lowest all-ten mean=(32+2×1)/10=3.4; highest=(32+2×5)/10=4.2. These bounds enumerate possible missing values on the allowed scale; they do not express 95% repeated-sampling coverage or indicate which values are likely.
4C. Outcomes from the same person may share ability, habits or conditions. Four people provide four person-level units, with repeated observations that may be correlated. Ask how assignment occurred, how tasks are ordered, whether conditions changed, and what dependence structure is plausible. A repeated-measures or clustered design needs suitable methods; treating 40 rows as independent can understate uncertainty.