May 23, 2013 ... Statistics is the science of conducting studies to collect, organize, summarize,
analyze, and draw conclusions from data. 4. Bluman Chapter 1.
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The Nature of Probability and Statistics
C H A P T E R
Outline Chapter 1 The Nature of Probabilityy and Statistics
Copyright © 2013 The McGraw‐Hill Companies, Inc. Permission required for reproduction or display.
The Nature of Probability and Statistics Objectives 1 2 3 4 5 6 7
1‐1 1‐2 1‐3 1 3 1‐4 1‐5
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Descriptive and Inferential Statistics Variables and Types of Data Data Collection and Sampling Techniques Data Collection and Sampling Techniques Observational and Experimental Studies Uses and Misuses of Statistics
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C H A P T E R
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Introduction
Demonstrate knowledge of statistical terms. Differentiate between the two branches of statistics. Identify types of data Identify types of data. Identify the measurement level for each variable. Identify the four basic sampling techniques. Explain the difference between an observational and an experimental study. Explain how statistics can be used and misused.
Statistics is the science of conducting studies to collect, organize, organize summarize, analyze, and draw conclusions from data.
Bluman Chapter 1
1-1 Descriptive and Inferential Statistics
A variable is a characteristic or attribute that can assume different values.
The values that a variable can assume are called data data.
A population consists of all subjects (human or otherwise) that are studied.
A sample is a subset of the population. Bluman Chapter 1
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1-1 Descriptive and Inferential Statistics
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Descriptive statistics consists of the collection, organization, summarization, and presentation of data.
Inferential statistics consists of generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables, and making predictions. Bluman Chapter 1
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1-2 Recorded Values and Boundaries
1-2 Variables and Types of Data Data Qualitative Categorical
Variable Length
Recorded Value 15 centimeters (cm) Temperature 86 Fahrenheit (F) Time 0.43 second (sec) Mass 1.6 grams (g)
Quantitative Qua t tat e Numerical, Can be ranked
Discrete
Continuous
Countable 5, 29, 8000, etc.
Can be decimals 2.59, 312.1, etc.
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1-2 Variables and Types of Data
2 2.
85.5-86.5 F 0.425-0.435 sec 1.55-1.65 g 8
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1-2 Variables and Types of Data
Levels of Measurement 1.
Boundaries 14.5-15.5 cm
Determine the measurement level.
Nominal – categorical (names)
Variable
Ordinal – nominal, nominal plus can be ranked (order)
Nominal Ordinal Interval
Hair Color
Yes
No
Zip Code
Yes
No
Yes
Yes
No
Ratio Level Nominal Nominal
3.
Interval – ordinal, plus intervals are consistent
Letter Grade ACT Score
Yes
Yes
Yes
No
Interval
4.
Ratio – interval, plus ratios are consistent, true zero
Height
Yes
Yes
Yes
Yes
Ratio
Age
Yes
Yes
Yes
Yes
Ratio
Temperature (F)
Yes
Yes
Yes
No
Interval
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1-3 Data Collection and Sampling Techniques
1-4 Observational and Experimental Studies
Some Sampling Techniques
Random – random number generator
S t Systematic ti – every kth subject bj t
Stratified – divide population into “layers”
Cluster – use intact groups
Convenient – mall surveys Bluman Chapter 1
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Ordinal
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In an observational study, study the researcher merely observes and tries to draw conclusions based on the observations. The researcher manipulates the independent (explanatory) variable and tries to determine how the manipulation influences the dependent (outcome) variable in an experimental study. study A confounding variable influences the dependent variable but cannot be separated from the independent variable. Bluman Chapter 1
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1-5 Uses and Misuses of Statistics
1-5 Uses and Misuses of Statistics
Suspect Samples Is
the sample large enough?
How
Are
different values used to represent the same data?
was the sample selected?
Is I
the th sample l representative t ti off the th population?
Detached Statistics One
Ambiguous Averages
What
particular measure of average was used and why?
Bluman Chapter 1
Changing the Subject
third fewer calories…….than what?
Implied Connections Studies
suggest that some people may understand what this statement means.
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1-5 Uses and Misuses of Statistics
Misleading Graphs Are
the scales for the x-axis and y-axis appropriate for the data?
Faulty Survey Questions Do
you feel that statistics teachers should be paid higher salaries?
Do
you favor increasing tuition so that colleges can pay statistics teachers higher salaries? Bluman Chapter 1
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