Question 4: Are the conclusions justified by the data?
`It seems therefore that as we get older our ears get bigger (on average by 0.22 mm a year)’. This is a cross-sectional not a longitudinal study, and the uncertainty in the estimate should be included. Strictly speaking, the conclusions should read `It seems therefore that older people have bigger ears (on average by between 0.17 and 0.27 mm per year of age)’. It could be that the ears of different birth cohorts differ. After all, different birth cohorts have different mean heights at the same age.
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