1- Freely select the continuous system parameters to be estimated (a secondary system is appropriate), specify the sampling time, and convert to a discrete system. Also describe the step response to be estimated.
2- Perform a least-squares estimation simulation with white noise (specifying the magnitude of variance) added to the target, and consider the estimation accuracy of the least-squares estimation method. (For example, studying estimated values by changing the input signal cycle and target sampling period, studying MSE, studying returning discrete estimates to a continuous system, etc.)

3- The least squares estimation was performed on the attached data rep20.dat using the estimation software Rivdat_cor2018.
Consider the results. Also consider the results of applying the auxiliary variable method.