Key Statistical Concepts and Hypothesis Testing
Multiple Choice Section
- If p is greater than alpha in a hypothesis test, do not reject the null hypothesis.
- The form of a relationship determines the effect of the independent variable (IV) on the dependent variable (DV).
- Degrees of freedom for chi-square: (rows – 1) x (columns – 1)
- ANOVA compares the means of more than 3 groups. A t-test compares 2 groups.
- The direction of a relationship between two interval/ratio variables depends on the sign of r and b.
- The significance of a relationship determines
Key Concepts in Statistical Sampling and Analysis
Key Concepts in Statistical Sampling and Analysis
Sampling and Population
- Which of the following is not an advantage of using a sample versus a census?
Ready access to respondents. - Which of the following refers to the basic level of investigation?
A sample unit. - Which of the following describes an entire group under study as specified by the objectives of the research project?
Population. - Of the following, which is not true of nonprobability samples?
Can compute the chances of any one population member
Statistical Concepts and Methods
Module 1: Core Statistical Concepts
Parameters and Statistics
A parameter summarizes a population (e.g., mean, median, standard deviation). Parameters are constant but usually unknown. A statistic is calculated from a sample (e.g., sample mean) and used to estimate parameters. Statistics are random and depend on the sample.
Point Estimates
A point estimate is a sample value used to estimate a specific population parameter. For instance, the sample mean can be a point estimate for the population mean.
Read MoreProspective Epidemiological Studies: Risk & Incidence
Prospective Epidemiological Studies
Prospective (Follow-Up) Study:
- A type of cohort study which analyzes risk factors and follows a group of people who do not have the disease, using correlations to determine the absolute risk of subject contraction.
- Prospective = cause → effect
- Cohort = group of people who share a common characteristic or experience within a defined period (e.g., are born, are exposed to a drug or vaccine or pollutant, or undergo a certain medical procedure).
- Two groups of patients
Statistical Inference: Sampling, Bootstrapping, and Confidence Intervals
Packages: Infer (sampling), ggplot2 for visualization, tidyr for data manipulation (part of tidyverse), dplyr for data wrangling, and readr for spreadsheet data.
Sampling Techniques
Sampling: Use rep_sample_n for random draws from a population, ensuring unbiased samples. As replicates increase, the sampling distribution becomes more symmetric and bell-shaped. As sample size (n) increases, variability (SD) for the sampling distribution decreases.
Population Terminology
Population Terminology:
- Population:
Hypothesis Formulation in Research: Types and Uses
Hypothesis Formulation
Scenarios show us what we are looking for or trying to prove and can be defined as tentative explanations of the phenomenon under investigation, made by way of propositions. A variable is a property that may vary (to acquire different values) and whose variation is susceptible to measurement.
Research: Hypotheses, Questions, and Objectives
Assumptions commonly arise from the objectives and research questions.
Origin of Hypotheses
Our hypotheses can arise from a postulate of a theory,
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