An approximation of a number, based on reasonable assumptions. <ul>3 </ul>
When is sampling used to estimate a population? <ul>4 </ul>
Sampling is used when it is not possible to count every member of a population because there are too many, they are too spread out, or not all the members of the population can be found. <ul>4 </ul>
What causes populations to change in size? <ul>5 </ul>
New members enter the population or members leave the population. <ul>5 </ul>
What do scientists mean by BIRTH RATE & DEATH RATE? <ul>6 </ul>
Birth Rate Number of births in a population in a certain amount of time. <ul>6 </ul>Death Rate Number of deaths in a population in a certain amount of time.