Compressive strength of concrete after different curing periods
Use this page to explain that the regression model with β0, β1 and σ replaced by estimates provides an estimate of the response distribution at any new x-value.
The grey band represents the fitted regression line ± twice the estimated standard deviation of the model error. Use the slider to show the estimated normal distribution of compressive strength after any curing period.
The mean of this estimated distribution (i.e. the prediction from the least squares line) provides a point prediction.
The data set arose from experiments that were performed to assess how the compressive strength of concrete is affected by its curing time. Five samples of concrete of the same composition were mixed. The compressive strength (mPa) of one sample was measured after each of 2, 7, 14, 21 and 28 days. (Testing is destructive, so different samples were needed for each curing period.)
Curing period (days) | Compressive strength (mPa) | ||
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