Suppose that x is a random variable with mean 30 and standard deviation 10. also suppose that y is a random variable with mean 20 and standard deviation 8. assume that the correlation between x and y is 0.4. find the mean and standard deviation of the random variable z for each of the following cases. be sure to show your work. a. z= 2 + 10x. b. z = x + y. c. z = −5x − 3y

The figure shows triangle def and line segment bc, which is parallel to ef: triangle def has a point b on side de and point c on side df. the line bc is parallel to the line ef. part a: is triangle def similar to triangle dbc? explain using what you know about triangle similarity. part b: which line segment on triangle dbc corresponds to line segment ef? explain your answer. part c: which angle on triangle dbc corresponds to angle f? explain your answer. asap