# random walk

1. ### Expected number of events in a simple birth-death process.

I have a simple birth-death process with parameters, beta=4/5v and the initial population size is 6. I have calculated that the birth rate= 4/9 and the death rate=5/9 but is there a way of calculating how many events (births and deaths) there will be until this population dies out? I have a...
2. ### Time series help, Derive COV in a random walk process

I could use some help deriving the covariance between Y_t and Y_t+h given the random walk process Y_t = Y_t-1+e_t And also the correlation between Y_t and Y_t+h Got stuck.. :( Also got another problem where i need to state whether pbl_t is correlated with e_(t-1) in this regression q_t=...
3. ### Random Walk in 2D

Please check the image. I need the asked probabilities. I know it is easy for u but my knowledge about probability is not good :) Thank you
4. ### Unit Root

What's this about? I'm new to econometrics and i'm trying to understand this conceptually. I know it has to do with nonstationarity (mean, variance and covariance changes over time) and the term "random walk" (the next step is the last one plus a random step) but what's the idea of a unit root...