1. Three things influence the margin of error in a confidence interval estimate of a population mean: sample size, variability in the population, and confidence level. For each of these quantities separately, explain briefly what happens to the margin of error as that quantity increases.
Answer: As sample size increases, the margin of error decreases. As the variability in the population increases, the margin of error increases. As the confidence level increases, the margin of error increases. Incidentally, population variability is not something we can usually control, but more meticulous collection of data can reduce the variability in our measurements. The third of these—the relationship between confidence level and margin of error seems contradictory to many students because they are confusing accuracy (confidence level) and precision (margin of error). If you want to be surer of hitting a target with a spotlight, then you make your spotlight bigger.
the three things influence the margin of error in a confidence interval estimate of a population mean - sample size variability in the population and confident level as the variability in the population increases the margin of error increases. as the cofidence level increases, the margin of error increases.
This survey will not be reliable as it is chosen for convenience; the first 120 students to arrive in school on a particular morning and this collection of individuals may not be a representative of the population. The study may become biased because it does not take into account the latecomers among the students which might have been changed the study from systematically favoring certain outcomes.
