In the population, 8% of males have had a kidney stone. suppose a medical researcher randomly selects two males from a large population. let a represent the event "the first male has had a kidney stone." let b represent the event "the second male has had a kidney stone." true or false? a and b are independent events.

The event that a "the first male has had a kidney stone" and b "the second male has had a kidney stone" is true. Random selection is used by the medical researcher in selecting two males from the population. Since simple random sample is defined as a subset of a statistical population wherein each member has an equal probability of being chosen, even if the probability is only 8%, males a and b may really have had a kidney stone.  

The arrangements of lipids in the membrane makes the cell semi permeable .