Histogram showing the galactic latitude distribution of low (solid line) and high (dashed line) variability stars for each spectral type. Sample selection ensured the orientation of the Kepler field on the plane did not introduce biases. An equal sample of high and low variability stars from each magnitude bin was also selected. The increased number of high variability F stars at low galactic latitudes may arise from giant contamination of the sample (see Sect. 3.3).