New Zealand Own-Price Food Elasticity Values by Income Quintile (lowest to highest), 2006−2010.

*Bold if 95% CI excludes the null. ** Geometric mean given ratios, and excluding ‘undefined’ estimates. † Calculated assuming no covariance. ‡ Ordinary least squares regression using the inverse of the variance of each PE as the weight, and the midpoints of the quintiles coded a 0, 0.25, 0.5, 0.75 and 1.0 such that the beta coefficient gives the change from the middle. £ Calculated as (Total own-PE+(0.5×absolute))/(Total own-PE −(0.5×absolute)), where: total own-PE = the own-PE before stratifying by income; absolute = the OLS regression estimated absolute difference in own-PE between the first and fifth quintiles of income. For example, for fruit the ratio = (−0.65 + (0.5×−0.08))/(−0.65 − (0.5×−0.08)) = 1.13.Undef = undefined (due to OLS regression estimate predicting a positive own-PE for the high income quintile).