1. A fish researcher has 8 Mangrove Rivulus fish from 3 lineages that vary in terms of their tolerance of salinity: 2 fish only tolerate low salinity, 3 fish only tolerate high salinity, and 3 fish have no salinity requirement. Four fish are selected at random without replacement. If X is the number that tolerate low salinity and Y is the number that tolerate high salinity, find:
2. the joint probability distribution of X and Y.
   1. Make a table that has X values in the first row, and Y values in the first column. Probabilities of each combination of (X,Y) should be in the interior of the table.
   2. Add the marginal distributions of the numbers of fish that tolerate low salinity (X) and high salinity (Y).
3. the probability that one fish is selected with low salinity, and one fish is selected with high salinity tolerance, i.e., P(X = 1, Y = 1)
4. the probability that one fish is selected with high salinity tolerance, given one fish is selected with low salinity, i.e., P(Y=1 | X=1)
5. the probability that only fish that have no salinity preference are selected, i.e., P(X=0,Y=0)
6. the mean value of:
7. fish that tolerate low salinity (X) and its meaning, and
8. fish that tolerate high salinity (Y) and its meaning
9. the covariance between fish that tolerate low salinity (X) and fish that tolerate high salinity (Y), and explain its meaning.