How to Round in R

How to Round in R This is a good source

Chebyshev’s Theorem Excel Calculator

Chebyshev’s Excel Calculator Chebyshev’s Theorem can be used for any type of distribution, but if the problem says the distribution is “bell shaped,” use the Empirical Rule unless the problem specifically says to use Chebyshev’s. Note: an alternative spelling is Chebychev. Chebyshev’s only applies to problems where the K is > 1. In our MSL […]

Correlation and Chi-square Tests for Independence

The word “correlate” has several meanings, e.g. “If two or more facts, numbers, etc. correlate or are correlated, there is a relationship between them” (Cambridge Dictionary, n.d.) And “to show that a close connection exists between (two or more things)” (Merriam-Webster, 2019)  Also, “to show that two things are connected.” (Macmillan, n.d.) In statistics, we often […]

Empirical Rule and z-score Probability

Empirical Rule The Empirical Rule applies to a normal, bell-shaped curve than is symmetrical about the mean. It states that within one standard deviation of the mean (both left-side and right-side) there is about 68% of the data; within two standard deviations of the mean (both left-side and right-side) there is about 95% of the data; […]

Hypothesis Tests Simplified: The Big Picture of Statistics

Alt-text: A visual representation of the poll conducted about the opinions of Fast Technologies customers about the quality of the hard drive. The large population, which represents all Fast customers, and data was produced from 1082 of these customers by asking them how many stars they would rate the product. In the data set we have 1082 responses, and exploratory data analysis tells us that 65% gave the product 4 stars. Using both probability and inference, we can draw the conclusion that we are 95% sure that the population percentage is within 3% of 65% (i.e. between 62% and 68%).

The Big Picture of Statistics¹ The process of statistics starts when we identify what group we want to study or learn something about. We call this group the population. Note that the word “population” here (and in the entire course) is not just used to refer to people; it is used in the broader statistical […]

The Impact of Innumeracy

By the time we reach voting age, almost all Americans have at least a high school education. That means we have been exposed to numerous math courses, and hopefully passed them. But that does not mean we have a good sense of numbers. Innumeracy in the modern sense means that one does not have a […]