Frequency comparisons of the sample. The figure shows the comparisons of the periods determined from different datasets. For Pan-STARRS, the Sesar et al. (2017) catalogue period was used, for Gaia DR3, the Gaia RR Lyrae catalogue period was used, and for K2, our calculated values were used, which we obtained with the Lomb–Scargle periodogram method. The plot symbols are colour-coded based on the Pan-STARRS vs. K2 frequency comparison. Green dots indicate the stars that have matching frequencies, blue dots indicate the stars that have an alias of 1 or 2 cycles/day in their Pan-STARRS frequencies, and red dots signify the stars that have discrepancies between their K2 and Pan-STARRS frequencies that are not aliases. Black circles mark the stars that we found to be misclassified in the Sesar et al. (2017) catalogue.