DESCRIPTIVE STATISTICS - FREQUENCY DISTRIBUTION.pdf

descriptive statistics

1. Descriptive Statistics

2. LEARNING GOAL
•
Understand the principle of descriptive
statistics;
•
Apply knowledge as to the selection of the basic
features of the data in descriptive statistics;
•
Apply knowledge as to make summary about
sample and the measure.

3. DESCRIPTIVE STATISTICS
Purpose–to describe or summarize data in a
parsimonious manner
Fourtypes
Central tendency
Variability
Relative position
Relationships

4. A mathematical function
FREQUENCY DISTRIBUTION
•
It is an organized tabulation of
the number of individuals located
in different categories in
different levels of measurement.
•
It is a representation, either in a
graphical or tabular format

5. A mathematical function
FREQUENCY DISTRIBUTION
•Frequency distribution is used to organize the collected data in table form.
The data could be marks scored by students, temperatures of different
towns, points scored in a volleyball match, etc. After data collection, we have
to show data in a meaningful manner for better understanding. Organize the
data in such a way that all its features are summarized in a table.

6. A mathematical function
FREQUENCY DISTRIBUTION
Scores of 10 Students in Math
Quiz
15, 17, 20, 15, 20, 17, 17, 14,
14, 20

7. Types of Frequency Distribution Table
FREQUENCY DISTRIBUTION
Grouped Frequency Distribution Table
To arrange a large number of
observations or data, we use grouped
frequency distribution table. In this, we
form class intervals to tally the
frequency for the data that belongs to
that particular class interval.
Ungrouped Frequency Distribution Table
In the ungrouped frequency distribution
table, we don't make class intervals, we
write the accurate frequency of
individual data.

8. Example:
Marks obtained by 20 students in the test are as follows.
5, 10, 20, 15, 5, 20, 20, 15, 15, 15, 10, 10, 10, 20, 15, 5, 18, 18, 18, 18.
Grouped Ungrouped

9. Symmetrical Distribution
Shape of Distribution
•a symmetric
distribution is a
distribution in which the
left and right sides mirror
each other.

10. Mean
Median
Mode
The average value
The middle value
The value that occurs most often
VOCABULARY

11. Symmetrical Distribution
Shape of Distribution
•a symmetric
distribution is a
distribution in which the
left and right sides mirror
each other.

12. Symmetrical Distribution
Shape of Distribution
1)No skewness(Zero skewness):
if the values of variable are
equidistance from the mean have equal
frequency ,then the distribution is said
to have symmetric or zero skewness.

13. Symmetrical Distribution
Shape of Distribution
Positive skewness right skewed: If the
frequency of the values of the variable
lower than the mean have high
frequencies compared to the
frequencies associated with the values
of variables higher than the mean.
mean>median>mode

14. Symmetrical Distribution
Shape of Distribution
Negative skewness right skewed:
mode<median<mean

15. Symmetrical Distribution
Shape of Distribution

21. Shape f Distribution
Pearson’s median skewness of the number of sunspots
observed per year:
•Mean = 48.6
•Median = 39
•Standard deviation= 39.5

22. •
Counts how many times data
occurs (frequency)
•
Good for small amounts of data
best for quantitative univariate data
DOT PLOT

23. •
Can use more than one to
compare data on the same graph
•
Good for large amounts of data
best for quantitative univariate data
BOX & WHISKER PLOT

24. best for quantitative univariate data
•
Counts how many times data
occurs between set ranges
•
Good for large amounts of data
HISTOGRAM

25. best for quantitative bivariate data
SCATTER PLOT
•
Great for analyzing correlation
between two variables
•
Good for large amounts of data

26. Which of the following is best for determining correlation?
QUIZ TIME
C. Histogram
B. Scatter Plot
A. Box & Whisker Plot

27. A. Box & Whisker Plot
C. Histogram
B. Scatter Plot
Which of the following is best for determining correlation?
QUIZ TIME

28. Which of the following is best for a large amount of data?
QUIZ TIME
A. Line Graph
C. Histogram
B. Dot Plot

29. QUIZ TIME
Which of the following is best for a large amount of data?
A. Line Graph
C. Histogram
B. Dot Plot

30. SubmitonGoogle Classroom
ASSIGNMENT
•
Create a question to ask your
classmates, friends, and family.
•
Ask your question to at least 10
people and collect the data.