Table 5

Change in between- and within-subject variance when excluding explanatory variables from full linear regression model

Variable excluded from full model900 MHz1800 MHzPMax (%)
Change in variance (%)Change in variance (%)Change in variance (%)
Between subjectsWithin subjectsBetween subjectsWithin subjectsBetween subjectsWithin subjects
Variables that can only vary between subjects
    Study centre*373633
    Time period000
    SMP model122
    Inside buildings†111
    Moving in vehicle†122
Variables that can vary between calls within subjects
    Duration of call289098394
    Time of call091205
  • *Excluding study centre from a model that does not include operator (in a model including operator and study centre, study centre is fully explained).

  • †Restricted set of study centres: not including Denmark, France, Germany, Sweden or UK North 1.

  • SMP, software-modified phone.