how to determine if a correlation is structurally similar how to measure equivalence of a regression model does age group effect affect volume how to determine age group effect in regression ________ is a statistical relationship between the volume of mail sent and time over time. how to find age group effects in r ____ is the coefficient between volume of mail sent in the years 2001-2012 when does volume of mail change in relation to time how to find age group effect in data age group effect on volume of mail how many years of mail volume are there for each age group? how many regressions for age group mail how to find if age group effect can age groups have different relationship how to determine whether a relationship exists between different age groups? how to test age group relationships in r how to determine age group based relationship how to determine equivalence of relationship between multiple regressions can you use r to test age group data? what relationship exists between time period and volume of mail sent