Please help asap

The brightness level Y of a pixel of a TV screen is 90% of the time described by a Gaussian random variable with mean 128 and variance 64. However, 5% of the time the pixel is defective and it is never on (always black) , so that Y = 0. The remaining 5% of the time the pixel is always white, so Y = 255. For this mixed random variable 1. Give the mathematical form of the pdf fy (y) using delta functions 8(.) and gaussian pdf. Sketch the pdf. 2. Give the mathematical form of the cdf Fy (y) using unit step function u(.) and sketch the pdf. 3. What is the probability the pixel brightness Y > 200