Statistical Indicators and Statistical Thinking - PowerPoint PPT Presentation

Loading...

PPT – Statistical Indicators and Statistical Thinking PowerPoint presentation | free to download - id: 68a15e-MmMzN



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Statistical Indicators and Statistical Thinking

Description:

Statistical Indicators and Statistical Thinking Dr. T S G Peiris Department of Mathematics * – PowerPoint PPT presentation

Number of Views:374
Avg rating:3.0/5.0
Slides: 45
Provided by: tosh48
Learn more at: http://www.math.mrt.ac.lk
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Statistical Indicators and Statistical Thinking


1
Statistical IndicatorsandStatistical Thinking
Dr. T S G Peiris Department of Mathematics
1
2
  • What is statistics?

  • Why do we do statistics?

To understand and explain the variability
2
3
Why data
  • As the global economy becomes increasingly
    electronic , the application of statistics to
    business and day to day applications has been
    increasing fast.

3
4
Why data are needed?
  • Obtaining appropriate data is essential in
    conducting business/teaching/etc
  • Data contain information needed to make a more
    informal decision in a particular situation.

4
5
The growth and development of statistics
  • Widespread availability of software tools had led
    to an ever increasing application of statistical
    methods to business decision making.
  • Today managers face problems/burdens, not having
    to make more and more decisions based on larger
    and larger volumes of data.

5
6
  • Why we want to know about statistics?

Managers/Processionals have access to a large
amount of data. Lack of knowledge of data and
its variability by the managers is difficult to
survive due to competition. That is to use
available data to make decisions
6
7
  • A market researcher needs to assess product
    characteristics to distinguish one product from
    another
  • An investor wants to determine what firms are
    likely to have accelerated growth
  • A lecturer wants to know the duration of which
    students access his notes in the website

7
8
  • Dean of a Faculty wants to how students performed
    in an exam
  • Students wants compare marks with others
  • An engineer wants to know how traffic pass at a
    busy junction
  • Farmer wants to about prices of vegetables

8
9
In todays world
  • we are constantly being bombarded with
    statistics and statistical information. For
    example
  • customer surveys
  • medical news
  • political polls
  • economic predictions
  • marketing information
  • scanner data
  • How can we make sense out of all this data?
  • How do we differentiate valid from flawed claims?
  • What is statistics?

9
10
Statistics
Data
Information
  • Statistics is a way to get information from data

Information Knowledge communicated concerning
some particular fact.
Data Facts,, collected together for reference or
information.
Statistics is a tool for creating new
understanding from data.
10
11
Key statistical concepts (Statistical Thinking)
Population
Sample
Subset
Parameters
Statistics
11
12
Key statistical concepts (Statistical
Thinking)
  • Population
  • A population is the group of all items of
    interest to a statistics practitioner.
  • Frequently very large sometimes infinite.
  • Sample
  • A sample is a set of data drawn from the
    population.
  • Potentially very large, but less than the
    population.
  • .

12
13
Key statistical concepts (Statistical Thinking)
  • Parameters
  • A descriptive measure of a population.
  • Statistics
  • A descriptive measure of a sample.

13
14
Statistical inference (Decisions)
  • Statistical inference is the process of making an
    estimate, prediction, or decision about a
    population based on a sample.

Population
Sample
Inference
Statistic
Parameter
What can we infer about a populations parameters
based on a samples statistics?
14
15
Stats anxiety
  • A student is anxious about his statistics course,
    after he had heard that the course is difficult.
    The lecturer provides last semesters final exam
    marks to the student. What can be discerned from
    this list of numbers?

Statistics
Data
Information
List of last terms marks.
New information derived about the statistics
class.
95 89 70 65 78 57
e.g. Class average, proportion of class
receiving Fs, most frequent mark, marks
distribution, etc.
15
16
Thus statistic
  • is a quantity that is calculated from a sample of
    data.
  • It is used to give information about unknown
    values in the corresponding population.

16
17
Statistical Indicator
  • Derived from the sample
  • A single or composite value to represent a
    variability of the population
  • Students performance indicators
  • University performance indicators
  • Educational indicators
  • Ecological indicators
  • Human Resource Indicators
  • Sport indicators
  • Health indicators
  • Climate indicator
  • Business indicators

18
Statistical Thinking
  • As today's good decisions are driven by data.
    Professionals are increasingly required to
    justify decisions on the basis of data
  • Statistical thinking is a science assisting you
    to make decisions under uncertainties
  • To make thinking easier we use statistical
    indicators

19
Indicators to measure central tendency
20
Indicators to measure central tendency
  • Mean

Weighted mean
In some cases, the data are weighted according to
its importance
21
Variation in weighted mean
22
Are both are the same?
What is the indicator to check the association?
23
Median67 - as an indicator
24
Selecting Mode as an indicator
25
Indicators to Measure dispersion
  • (a) Sample variance

68, 12.9
(b) Range
37,93
26
Use of Standard Deviation (SD) as an indicator
27
Quality of information and variation are
inversely related
  • The larger the variation in the data, the lower
    the quality of the data (i.e., information) the
    Devil is in the Deviations

28
  • Other indicators to measure dispersion are Mean
    Absolute Deviation (MAD) and Coefficient of
    Variability (CV)

29
Why indicator CV is useful?
  • Eg. A manufacturer of television tubes has two
    types of tubes namely A and B. Mean life time
    tubes A and B are 1495 hrs and 1875 and SD of
    tubes are 220 hrs and 310 hrs respectively.
  • The CV of A 14.7
  • and CV of B 16.5

30
Indicators to Measure Percentiles
  • First quartile (Q1) The sample 25th percentile
    (P25)
  • Second quartile (Q2) The sample 50th
    percentile (P50) median
  • Third quartile (Q3) The sample 75th percentile
    (P75)
  • Inter quartile range (IQR) Q3 Q1
  • Desired Percentile

31
Indicator to measure association between two
variables
Correlation Coefficient
32
Use of statistical indictors for decision making
  • Use of Z Score

Consumer Price Index CCPI is an indicator to
measure of the average change in the prices paid
by consumers for a specific basket of goods and
services over time in a country
33
Z Score as a statistical indicator
Distribution of raw marks
34
Z Score as a statistical indicator
Distribution of new indicator Z score
35
Relationship between raw marks and Z score
36
Consumer Price Index CCPI
  • It is a statistical indicator to measure of the
    average change in the prices paid by consumers
    for a specific basket of goods and services over
    time in a country.

Colombo Consumer Price Index (CCPI)
37
Weights used for Colombo Consumer Price Index
(CCPI) CCPI_N
Items Weight
Food and Beverages 46.71
Cloth and Footwear 3.08
Housing, Water, Electricity 18.29
Furnishing 3.22
Health 4.18
Transport 9.47
Communication 4.42
Recreation Culture 2.18
Education 5.79
Miscellaneous 2.65
38
Grade Point Average _GPA
39
Use of statistical indictors for decision making
  • Body Mass Index
  • Body Mass Index (BMI) is an indicator
    calculated from a person's weight and height.
  • BMI provides a reliable indicator of body
    fatness for most people and is used to screen for
    weight categories that may lead to health
    problems .
  • HAS THIS UPDATED TO SL?

40
BMI - Indicator
  • BMI indicates you are
  • Underweight for BMI less than 18.5,
  • Normal - 18.5 - 24.9
  • Overweight - 25.0 - 29.9
  • Obese gt 30.0

41
BMI - Indicator
  • high blood pressure (hypertension)
  • high LDL-cholesterol ("bad" cholesterol)
  • low HDL-cholesterol ("good" cholesterol)
  • high triglycerides
  • high blood glucose (sugar)
  • family history of premature heart disease
  • physical inactivity
  • cigarette smoking

42
Use of statistical indictors for decision making
  • Human Development Index
  • is an indicator
  • to rank countries by level of "human
    development", which usually also implies whether
    a country is a developed, developing or under
    developing

43
HDI - Indicator
  • Go to Websites

44
Thank youandBest Wishes
About PowerShow.com