. 2017 Mar 2;49:29. doi: 10.1186/s12711-017-0302-9

Table 6.

Operations required to calculate the correction factor

Step	Component	Number of operations
1	${(X_{1}^{'} X_{1})}^{- 1}$	$p_{1}$
2	$X_{1}^{'} X_{2} V a r ({\hat{β}}_{2}) X_{2}^{'} X_{1}$	$p_{1} p_{2}^{2} + p_{1}^{2} p_{2}$
3	Multiplying ${(X_{1}^{'} X_{1})}^{- 1}$ on both sides of step 2	$2 p_{1}^{2}$
4	$X_{1}^{'} X_{2} V a r ({\hat{β}}_{2}, {\hat{β}}_{1})$	$p_{1}^{2} p_{2}$
5	Multiplying ${(X_{1}^{'} X_{1})}^{- 1}$ on the left side of step 4	$p_{1}^{2}$
6	Addition to obtain correction factor for other fixed effects	$2 p_{1}^{2}$
7	Addition of step 6 to $V a r ({\hat{β}}_{1})$	$p_{1}^{2}$
8	Completing PEVMean	$p_{1}$
	Total calculations	$2 p_{1} + 6 p_{1}^{2} + p_{1} p_{2} (2 p_{1} + p_{2})$