Figure 7
Normality diagram of compressive strength (explanation: \({y}_{i}={(x}_{i}-\overline{x})/s\); \({\widetilde{y}}_{i}={\phi }^{-1}({u}_{i})\); \({p}_{i}=(3i-1)/(3n+1)=\phi ({u}_{i})\); \({x}_{i}\)—compressive strength results, ordered in ascending order; \(\overline{x}\)— arithmetic mean; s—standard deviation; \(\phi ({u}_{i})\)—standard normal distribution cumulative distribution function for compressive strength; \({p}_{i}\)—cumulative frequencies; i—index in ascending series; n—number of observations).
