Mathematics and Statistics

Statistics is a vocabulary-heavy discipline, full of words with highly specialized definitions (really, jargon!). Here are some key terms and definitions to get you started in statistics.

Hypothesis testing consists of two contradictory hypotheses or statements, a decision based on the data, and a conclusion. To perform a hypothesis test, a statistician will:

1. Set up two contradictory hypotheses.
2. Collect sample data (in homework problems, the data or summary statistics will be given to you).
3. Determine the correct distribution to perform the hypothesis test.
4. Analyze sample data by performing the calculations that ultimately will allow you to reject or decline to reject the null hypothesis.
5. Make a decision and write a meaningful conclusion.

The actual test begins by considering two hypotheses. They are called the null hypothesis and the alternative hypothesis. These hypotheses contain opposing viewpoints.

H₀: The null hypothesis: It is a statement of no difference between the variables—they are not related. This can often be considered the status quo and as a result if you cannot accept the null it requires some action.

H_a: The alternative hypothesis: It is a claim about the population that is contradictory to H₀ and what we conclude when we reject H₀. This is usually what the researcher is trying to prove.

Since the null and alternative hypotheses are contradictory, you must examine evidence to decide if you have enough evidence to reject the null hypothesis or not. The evidence is in the form of sample data.

After you have determined which hypothesis the sample supports, you make a decision. There are two options for a decision. They are "reject H₀" if the sample information favors the alternative hypothesis or "do not reject H₀" or "decline to reject H₀" if the sample information is insufficient to reject the null hypothesis.

Average or Mean are both words used to refer to a number that describes the central tendency of the data; there are several specialized averages or means, including the arithmetic mean, weighted mean, median, mode, and geometric mean.

The p-value is the probability that an event will happen purely by chance, assuming the null hypothesis is true. The smaller the p-value, the stronger the evidence is against the null hypothesis.

The standard deviation of a data set is a number that is equal to the square root of the variance and measures how far data values are from their mean. The notation differs for sample versus population: s for sample standard deviation and σ for population standard deviation.

"In research, statistical significance measures the probability of the null hypothesis being true compared to the acceptable level of uncertainty regarding the true answer. "  Read more at StatPearls

Illowsky, B., & Dean, S. (2023). Introductory statistics 2e. OpenStax. https://openstax.org/books/introductory-statistics-2e/pages/1-introduction

Tenny, S., & Abdelgawad, I. (2023). Statistical Significance. In StatPearls. StatPearls Publishing.