The graph shows observations and a regression line of the number of progeny on the tail length of male birds.
Which of the following can be inferred from the graph?
1
Producing less progeny decreases the tail length of the males.
2
Males cannot have a tail length lesser than 10 mm.
3
Males with longer tails tend to father more progeny.
4
For a male with a 25 mm tail, the expected number of progeny is 4.