It is necessary to test the null hypothesis (H0): The hologram display of machine parts gives the same visual perception as well as the technical drawing - H0:ݔҧ = ݕ ത. An alternative hypothesis (H1) is: Di splay of machine parts in the form of a hologram provides better visual perception than the one in the form of the technical drawing. If the null hypothesis is true then the alternative hypothesis is rejected. If the null hypothesis is incorrect alternative hypothesis is accepted and all assumptions are correct.