This is the README for the dataset "Data for cosmological analysis of modified gravity" The dataset is obtained using the public code EFTCosmoMC (https://github.com/EFTCAMB/EFTCosmoMC), which performs Monte Carlo exploration of the parameter space of modified gravity models. This dataset is divided in three main directories, each containing the data related to a different chapter of the dissertation. Each main directory contains two sub directories: -parameter_files: this directory contains the parameter files used to generate the chains. These are the input files for EFTCosmoMC, please refer to the EFTCosmoMC README for details. -chains: The chains are the output of the EFTCosmoMC code and are obtained using the input files in parameter_files. The chains consist of files with extention - .inputparams: a list of all the parameters used to create the related chains (these files are a summary of the inputs in the directory parameter_files) - .paramnames: a list of all the parameters stored in the chains. The ordering of the parameters is the same as in the .txt files - .ranges: ranges in which the parameters are allowed to vary in the EFTCosmoMC analysis - .likelihoods: a list of the likelihoods and cosmological dataset used to create the chains - .converge_stat: the convergence of the chains - .txt: these are the actual chains generated by EFTCosmoMC. Each column represents the value of one parameter, in the order given by the .paramnames file. Each row refers to a different step of the Monte Carlo sampling of EFTCosmoMC. The chains can be promptly analysed with GetDist, a Python package for analysing Monte Carlo samples (https://pypi.org/project/GetDist).