A catalyst researcher states that the diameters (in microns) of the pores in a new product catalyst she has made have an exponential distribution with parameter ë = 0.25 (35 pts).
(a) Determine the mean pore size.
(b) Determine the standard deviation of the pore diameters.
(c) What proportion of the pores are less than 3.0 microns in diameter?
(d) What proportion of the pores are greater than 11.0 microns in diameter?
(e) What is the median pore diameter?
(f) What is the third quartile of the pore distribution?
(g) What is the 99th percentile of the pore diameters?
I found that a and b both equal 4, but I am not sure where to start on part c.