Question

In the 1980s, the population of Pleasanton decreased by 10%. In the 1990s, its population increased by 30%. How does the population of Pleasanton at the end of the 1990s compare with its population in 1980

1. bonexptip
Let the population of Pleasanton in 1980= x
In 1980 it decreased by 10%
after a 10% decrement the population= x-10/100 = 0.9x
In the 1990s it increased by 30%
after a 30% increment, the population is
= 0.9x + (30/100 × 0.9x)
=0.9x +0.27x
=1.17x
Final population = 1.17x
initial population = x
change% = final – initial / initial × 100
= 1.17x-x/x × 100
= 17%
It is positive, it is 17% higher
A population, in statistics and other mathematical fields, is a discrete group of people, animals, or things that can be identified by one or more common characteristics for the purposes of data collection and analysis. To gather information about a large population, you typically collect data from samples.
The population is the sum of people surveyed. In this example, the population corresponds to the university under study, which is 250 people. Determine the sample size of the study. The sample size is the number of people the statistician surveys.