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So I am new to Time-Series and have started with some basic financial data. Since it was not covariance stationary, I transformed it by taking daily percentage changed. The data became stationary and I also concluded so by conducting Augmented DF Test. Here is the ACF & PACF plot of the transformed data:

enter image description here

I understand, that since both the plots don't clearly cut-off at some particular lag, this is not specifically a MA or an AR process, but maybe some ARMA process. But how do I now go about modelling my ARMA? How to conclude the p and q values? And most importantly, how do I validate all the assumptions of these processes?

EDIT 1: So, drawing from the above plots I have tried modelling an ARMA process with p & q values as 1 and here is the summary:

enter image description here

It seems like, even before any further analysis of residuals etc, since the coefficient of MA(1) is not significant enough, can I conclude that ARMA is not fit for the process? And so I should not use this model, and try for the AR model? I am completely in the blank here. Will keep this thread updated with my research.

Please help if possible!

Here is the original data (the one which is raw, not transformed, and is not covariance stationary):

2020-03-02,119.10955047607422
2020-03-03,114.64000701904295
2020-03-04,117.4726791381836
2020-03-05,111.70932006835938
2020-03-06,105.93614959716795
2020-03-09,91.5865478515625
2020-03-10,98.7025375366211
2020-03-11,94.05655670166016
2020-03-12,86.30345916748047
2020-03-13,101.84886932373048
2020-03-16,86.60730743408203
2020-03-17,91.90019989013672
2020-03-18,82.2259750366211
2020-03-19,83.6080093383789
2020-03-20,81.84371948242188
2020-03-23,77.4623794555664
2020-03-24,86.6759262084961
2020-03-25,89.91046905517578
2020-03-26,96.17372131347656
2020-03-27,89.3223648071289
2020-03-30,91.6453628540039
2020-03-31,88.24418640136719
2020-04-01,82.68665313720703
2020-04-02,85.774169921875
2020-04-03,83.23888397216797
2020-04-06,88.59666442871094
2020-04-07,89.7652816772461
2020-04-08,93.38996124267578
2020-04-09,101.76831817626952
2020-04-13,97.24242401123048
2020-04-14,94.57837677001952
2020-04-15,89.91383361816406
2020-04-16,86.48722839355469
2020-04-17,94.26146697998048
2020-04-20,90.824951171875
2020-04-21,88.19062805175781
2020-04-22,88.47782135009766
2020-04-23,88.52734375
2020-04-24,89.83460235595703
2020-04-27,93.70687866210938
2020-04-28,94.3704071044922
2020-04-29,96.91560363769531
2020-04-30,94.83587646484376
2020-05-01,92.35009002685548
2020-05-04,91.25080871582031
2020-05-05,91.1121597290039
2020-05-06,89.39884948730469
2020-05-07,90.32978057861328
2020-05-08,91.8053970336914
2020-05-11,89.10174560546875
2020-05-12,86.19011688232422
2020-05-13,83.21907043457031
2020-05-14,86.67538452148438
2020-05-15,85.07102966308594
2020-05-18,89.57711029052734
2020-05-19,87.81429290771484
2020-05-20,90.44862365722656
2020-05-21,89.29981231689453
2020-05-22,88.60657501220703
2020-05-26,94.89529418945312
2020-05-27,100.39173126220705
2020-05-28,98.89630126953124
2020-05-29,96.37091064453124
2020-06-01,97.6484603881836
2020-06-02,97.97528076171876
2020-06-03,103.26374053955078
2020-06-04,105.41280364990234
2020-06-05,110.15657806396484
2020-06-08,112.35514831542969
2020-06-09,109.47323608398438
2020-06-10,105.03646850585938
2020-06-11,96.2718734741211
2020-06-12,98.90621185302734
2020-06-15,100.27288818359376
2020-06-16,101.0750732421875
2020-06-17,98.5199737548828
2020-06-18,97.98518371582031
2020-06-19,96.8660888671875
2020-06-22,95.81631469726562
2020-06-23,96.98493194580078
2020-06-24,93.74649047851562
2020-06-25,97.01464080810548
2020-06-26,91.69645690917969
2020-06-29,92.10250854492188
2020-06-30,93.15227508544922
2020-07-01,92.36000061035156
2020-07-02,92.66000366210938
2020-07-06,95.0
2020-07-07,92.31999969482422
2020-07-08,93.3000030517578
2020-07-09,91.27999877929688
2020-07-10,96.2699966430664
2020-07-13,97.6500015258789
2020-07-14,98.20999908447266
2020-07-15,99.7300033569336
2020-07-16,100.01000213623048
2020-07-17,98.16000366210938
2020-07-20,97.3000030517578
2020-07-21,99.41000366210938
2020-07-22,98.69000244140624
2020-07-23,98.9800033569336
2020-07-24,98.27999877929688
2020-07-27,96.9000015258789
2020-07-28,97.31999969482422
2020-07-29,99.68000030517578
2020-07-30,97.0199966430664
2020-07-31,96.63999938964844
2020-08-03,96.0999984741211
2020-08-04,95.5500030517578
2020-08-05,97.20999908447266
2020-08-06,97.23999786376952
2020-08-07,99.37999725341795
2020-08-10,100.63999938964844
2020-08-11,103.81999969482422
2020-08-12,102.94000244140624
2020-08-13,102.37000274658205
2020-08-14,102.41000366210938
2020-08-17,99.70999908447266
2020-08-18,98.31999969482422
2020-08-19,98.5500030517578
2020-08-20,97.37000274658205
2020-08-21,97.31999969482422

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