Chapter 1 Slides (PPT)

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Chapter 1
Statistics and the Scientific Method
Introduction
• Applied Statistics generalizes into 4-step process:
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Problem Definition/Description
Data Collection
Data Description/Summarization
Data Analysis/Interpretation/Communication
• Many methods exist to complete this process for
many types of data and experimental settings
Examples of Practical Problems
• New Drug Testing: Does a new drug improve patient
condition more so than an existing drug or placebo?
• Quality Control: Does a manufacturing facility
continue to have an acceptable rate of defectives?
• Political Polling: What proportion of adults favor a
particular political stance or candidate?
• Measuring Animal Poulations: How many fish of a
particular species live in a lake?
• Agricultural Production: Which of 4 varieties of
fertilizer give best results in grain production?
• Marketing: What levels of pricing and advertising
produce the highest profits for a new product?
Populations and Samples
• Population: All measurements of interest to
researcher
• Sample: Subset of population that is
obtained and to be analyzed
Population
Sample
Statistical Inference
• Goal: Make statements regarding a population
(or true state of nature) based on observations
from a sample.
– What can be said of the average measurement in a
population, when we obtain the average of a sample
from the population?
– Can we conclude success rates differ for two
treatments in nature (across a conceptual population
of units), based on a certain difference in success
rates in two samples of units that were assigned the
treatments

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