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The X-ray emission from blazars has been widely investigated using severalspace telescopes. In this work, we explored statistical properties of the X-rayvariability in the blazars S5 0716+714, OJ 287, Mkn 501 and RBS 2070 using thearchival observations from the XMM-Newton telescope between the period2002-2020. Several methods of timing and spectral analyses including fractionalvariability, minimum variability timescale, power spectral density analyses andcountrate distribution were performed. In addition, we fitted various spectralmodels to the observations as well as estimated hardness ratio. The resultsshow that the sources are moderately variable within the intra-day timescale.Three of the four sources exhibited a clear bi-modal pattern in their countratedistribution revealing possible indication of two distinct countrate states,that is, hard and soft countrate states. The slope indices of the powerspectral density were found to be centered around 0.5. Furthermore, the spectraof the sources were fitted with single power-law, broken power-law,log-parabolic and black-body+log-parabolic models (the latter only for OJ 287).We conclude that for most of the observations log-parabolic model was the bestfit. The power spectral density analysis revealed the variable nature of PSDslopes in the source light curves. The results of this analysis could indicatethe non-stationary nature of the blazar processes on intra-day timescales. Theobserved features can be explained within the context of current blazar models,in which the non-thermal emission mostly arises from kilo-parsec scalerelativistic jets.

X-ray timing and spectral variability properties of blazars S5 0716+714, OJ 287, Mrk 501, and RBS 2070