# Count 'em up

You have 1500 Escherichia coli cells in 1 mL of liquid. You gently shake the test tube, withdraw 100 $$\mu$$L of liquid, and deposit all of it onto a petri dish on which the cells grow. You come back 10 hours later and find that all the cells you deposited on the plate have grown into visible colonies. What is the expected variance in the number of colonies you count on your plate?