A component to be used in the assembly of a transmission mechanism is manufactured in a process for which the two quality characteristics of tensile strength (X1) and diameter (X2) are of importance. Twenty samples, each of size 4, are obtained from the process. For each component, measurements on the tensile strength and diameter are taken and are shown in Table 7-26. Construct a multivariate Hotelling's I2 control chart using an overall type I error probability of 0.01.