On the Surety Period of a Special Kind of Devices

The probability for a device to work properly after a certain period of time will be considered using the Strehler-Mildvan model. We will suppose that the functionality of a device depends on an unknown parameter , which decreases progressively in time. The device stops working if goes below a certain given value.We will use the method of maximum likelihood to estimate the parameters of the model and to estimate the probability of proper work at a future moment using the survival function