1.Population size: The total number of people in the group you are trying to study. If you were taking a random sample of people across the U.S., then your population size would be about 317 million. Similarly, if you are surveying your company, the size of the population is the total number of employees.
For a normal population distribution with mean and standard deviation , the distribution of the sample mean is normal, with mean and standard deviation . This result follows from the fact that any linear combination of independent normal random variables is also normally distributed.
