© The McGraw-Hill Companies, Inc., 2000 1-1 by Marc M. Triola & Mario F. Triola SLIDES PREPARED BY...
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Transcript of © The McGraw-Hill Companies, Inc., 2000 1-1 by Marc M. Triola & Mario F. Triola SLIDES PREPARED BY...
© The McGraw-Hill Companies, Inc., 2000
1-11-1
by by
Marc M. Triola & Mario F. TriolaMarc M. Triola & Mario F. Triola
SLIDES PREPARED BY SLIDES PREPARED BY
LLOYD R. JAISINGHLLOYD R. JAISINGH
MOREHEAD STATE UNIVERSITYMOREHEAD STATE UNIVERSITY
MOREHEAD KYMOREHEAD KY
(with modifications by DGE Robertson)(with modifications by DGE Robertson)
Biostatistics Biostatistics for the Biological and Health
Sciences
1-21-2
Chapter 1Chapter 1
IntroductionIntroduction
WCB/McGraw-Hill
© The McGraw-Hill Companies, Inc., 1998
© The McGraw-Hill Companies, Inc., 2000
1-31-3 OutlineOutline
1-1 Introduction 1-2 Types of Data 1-4 Data Collection and Data Collection and
Sampling Techniques Sampling Techniques 1-5 Computers and Calculators
© The McGraw-Hill Companies, Inc., 2000
1-51-5 ObjectivesObjectives
Demonstrate knowledge of all statistical terms.
Differentiate between the two branches of statistics.
Identify types of data.
© The McGraw-Hill Companies, Inc., 2000
1-61-6 ObjectivesObjectives
Identify the measurement level for each variable.
Identify the four basic sampling techniques.
© The McGraw-Hill Companies, Inc., 2000
1-81-8 1-1 Introduction1-1 Introduction
StatisticsStatistics consists of conducting studies to collect, organize, summarize and analyze data and to draw conclusions
© The McGraw-Hill Companies, Inc., 2000
1-91-91-1 Descriptive and Inferential 1-1 Descriptive and Inferential
StatisticsStatistics
DataData are the values (measurements or observations) that the variables can assume.
Variables whose values are determined by chance are called random variablesrandom variables.
© The McGraw-Hill Companies, Inc., 2000
1-101-101-1 Descriptive and Inferential 1-1 Descriptive and Inferential
StatisticsStatistics
A collection of data values forms a data set.data set.
Each value in the data set is called a data valuedata value or a datumdatum.
© The McGraw-Hill Companies, Inc., 2000
1-111-111-1 Descriptive and Inferential 1-1 Descriptive and Inferential
StatisticsStatistics
Descriptive statisticsDescriptive statistics consists of the collection, organization, summation and presentation of data.
© The McGraw-Hill Companies, Inc., 2000
1-121-121-1 Descriptive and Inferential 1-1 Descriptive and Inferential
StatisticsStatistics
A populationpopulation consists of all subjects (human or otherwise) that are being studied.
A samplesample is a subgroup of the population.
© The McGraw-Hill Companies, Inc., 2000
1-131-131-1 Descriptive and Inferential 1-1 Descriptive and Inferential
StatisticsStatistics
Inferential statisticsInferential statistics consists of generalizing from samples to populations, performing hypothesis testing, determining relationships among variables, and making predictions.
© The McGraw-Hill Companies, Inc., 2000
1-141-14 1-2 Variables and Types of Data1-2 Variables and Types of Data
Qualitative variablesQualitative variables are variables that can be placed into distinct categories, according to some characteristic or attribute. For example, gender (male or female).
© The McGraw-Hill Companies, Inc., 2000
1-151-15 1-2 Variables and Types of Data1-2 Variables and Types of Data
Quantitative variablesQuantitative variables are numerical in nature and can be ordered or ranked. Example: age is numerical and the values can be ranked.
© The McGraw-Hill Companies, Inc., 2000
1-161-16 1-2 Variables and Types of Data1-2 Variables and Types of Data
Discrete variablesDiscrete variables assume values that can be counted.
Continuous variablesContinuous variables can assume all values between any two specific values. They are obtained by measuring.
© The McGraw-Hill Companies, Inc., 2000
1-171-17 1-2 Variables and Types of Data1-2 Variables and Types of Data
The nominal level of measurementnominal level of measurement classifies data into mutually exclusive (nonoverlapping), exhausting categories in which no order or ranking can be imposed on the data.
© The McGraw-Hill Companies, Inc., 2000
1-181-18 1-2 Variables and Types of Data1-2 Variables and Types of Data
The ordinal level of measurementordinal level of measurement classifies data into categories that can be ranked; precise differences between the ranks do not exist.
© The McGraw-Hill Companies, Inc., 2000
1-191-19 1-2 Variables and Types of Data1-2 Variables and Types of Data
The interval level of measurementinterval level of measurement ranks data; precise differences between units of measure do exist; there is no meaningful zero.
© The McGraw-Hill Companies, Inc., 2000
1-201-201-2 Types of Data1-2 Types of Data
The ratio level of measurementratio level of measurement possesses all the characteristics of interval measurement, and there exists a true zero. In addition, true ratios exist for the same variable.
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1-211-211-4 Data Collection and Sampling 1-4 Data Collection and Sampling Techniques Techniques
Data can be collected in a variety of ways. One of the most common methods is
through the use of surveys. Surveys can be done by using a variety of
methods: Examples are telephone, mail questionnaires,
personal interviews, surveying records and direct observations.
© The McGraw-Hill Companies, Inc., 2000
1-221-221-4 Data Collection and Sampling 1-4 Data Collection and Sampling Techniques Techniques
To obtain samples that are unbiased, statisticians use four methods of sampling.
Random samplesRandom samples are selected by using chance methods or random numbers.
© The McGraw-Hill Companies, Inc., 2000
1-231-231-4 Data Collection and Sampling 1-4 Data Collection and Sampling Techniques Techniques
Systematic samplesSystematic samples are obtained by numbering each value in the population and then selecting the kth value.
© The McGraw-Hill Companies, Inc., 2000
1-241-241-4 Data Collection and Sampling 1-4 Data Collection and Sampling Techniques Techniques
Stratified samplesStratified samples are selected by dividing the population into groups (strata) according to some characteristic and then taking samples from each group.
© The McGraw-Hill Companies, Inc., 2000
1-251-251-4 Data Collection and Sampling 1-4 Data Collection and Sampling Techniques Techniques
Cluster samplesCluster samples are selected by dividing the population into groups and then taking samples of the groups.
© The McGraw-Hill Companies, Inc., 2000
1-251-251-4 Data Collection and Sampling 1-4 Data Collection and Sampling Techniques Techniques
Convenience samplesConvenience samples are when subjects are selected for convenience. (Often used in student research projects or by advertisers.)
© The McGraw-Hill Companies, Inc., 2000
1-261-26 1-5 Calculators 1-5 Calculators
Calculators make some statistical tests and numerical computations easier.
The TI-35 and TI-83 calculators perform 2-variable statistical calculations.
Must learn how to enter and perform statistical functions on your calculator.
© The McGraw-Hill Companies, Inc., 2000
1-261-261-5 Computers and Calculators 1-5 Computers and Calculators
Computers can perform more advanced statistical tests.
Many statistical packages are available. Examples are SPSS, SAS and MINITAB also Excel and QuattroPro.
Input and output from computer must understood and interpreted.