For the quarter just ended, BoSan Pty Ltd reported the following variances in one of its manufacturing departments:

Material price varianceUnfavourable

Material quantity varianceFavourable

Labour efficiency varianceFavourable

Labour rate varianceNegligible

The sum of the favourable variances above exceeded the unfavourable materials price variance by a considerable amount. The quality of the output from the department was the same as usual. Practically all of the raw material used in this quarter was purchased in this quarter. Is there any connection between these variances? If so, explain