University:
McNeese State University
Course:
MATH 231 | Elementary Probability and Statistical Inference
Academic year:

2024
Views:

344

Pages:

1
Author:

Tori K.

Math 231 1-3 Data Collection and Experimental Design Baldwin Designing a Statistical Study 1. Identify the variable(s) of interest (the focus) and the population of the study. 2. Develop a detailed plan for collecting data. If you use a sample, make sure the sample is representative of the population. 3. Collect data. 4. Describe the data, using the descriptive statistics techniques. 5. Interpret the data and make decisions about the population using inferential statistics. 6. Identify any possible errors. In an observational study, a researcher does no influence the responses. A researcher observes and measures characteristics of interest of part of a population but does not change the existing conditions. In an experiment, a researcher deliberately applies a treatment before observing the responses. A treatment is applied to part of the population, called a treatment group and responses are observed. Another part of the population may be used as a control group, in which no treatment is applied. The subjects in both groups are called experimental units. In many cases, subjects in this group are given a placebo, which is a harmless, fake treatment that is made to look like the real treatment. The responses of both groups can be compared and studied. Ex 1: Determine whether each study is an observational study or an experiment. 1. Researchers study the effect of vitamin D3 supplementation among patients with antibody deficiency or frequent respiratory tract infections. 70 patients receive 4000 IU of vitamin D3 daily for a year. Another group of 70 patients receive a placebo daily for one year. (Source: British Medical Journal) Experiment crit D) to b/c the the study subjects apples a treatment . 2. Researchers conduct a study to determine how confident Americans are in the economy. Researchers call 3040 U.S. adults and ask them to rate current U.S. economic conditions and whether the economy is getting better or worse. (Source: Gallup) Observational study since there's no treatment A simulation is the use of a mathematical or physical model to reproduce the conditions of a situation or process. Collecting data often involves the use of computers. Simulations allow you to study situations that are impractical or even dangerous to create in real life, and often they save time and money. Ex: Automobile manufactures use simulations with dummies to study the effects of crashes on humans. 1