1.) The most important thing that must be true about a sample so that you can make a valid inference about the population is that the sample must not be biased.
2.) It is important to take a random sample of the population you want to study because the population may be too large that it might be impossible or too expensive to conduct a survey on a population.
3.) An outlier is an observation point that is distant from other observations. It can be too small or too big compared to other observations.
The measure of center that is more affected by outliers in the data is the mean, because since the mean is obtained by the sum of the data divided by the number of the data set. Any 'too big' number or 'too small' number will affect the sum of the data set.
4.) Given that Sam
conducted a survey to find out the favorite weekend activity of the
students his middle school. He asked 20 of his classmates. He found out
that the favorite weekend activity of his middle school is playing
video games because 75% of the students he surveyed liked to play video
games.
Sam’s sample may not be valid because he drew a sample only from his class to make an inference about the entire middle school students.
For Sam to improve his survey to be more representative of his school he must draw a random sample from all the classes that make up the middle school.
