STATISTICAL TREATMENT in Research

1. STATISTICA
L
TREATMENT
Using the appropriate
statistical tool to arrive at
accurate and definite
interpretation of results.

2. STATISTICS
It is a science of collecting,
presenting, analyzing and
interpreting data to arrive at an
effective decision.

3. TYPES OF DATA
1. QUALITATIVE DATA
---- Non-numeric data
2. QUANTITATIVE DATA
---- Numeric data

4. CLASSIFICATION OF
STATISTICS
1. DESCRIPTIVE STATISTICS
---is a manner of organizing, presenting or
summarizing a set of data or observations in an
informative way.
2. INFERENTIAL STATISTICS
---proceeds from conducting a study of a subset
taken from a population.

5. NORMAL
DISTRIBUTION

6. PROPERTIES OF NORMAL
DISTRIBUTION
 Bell-shaped
 The mean, median, and mode are all equal and are
located at the center of the distribution.
 The distribution is symmetric.
 The total area under a normal curve is 1 or 100%
 The distribution is asymptotic.
 The location of the distribution is determined by the
mean and the standard deviation determines
dispersion of the distribution.

7. STANDARDIZED SCORE
(Z-value)
Formula:
Z =
𝑥 − µ
𝛿
z = Normal Value
X = value of any particular observation
µ = mean of the distribution
𝛿 = standard deviation

8. The scores of 120 students in a stat
preliminary examination show a bell-shaped
distribution. The mean score is 29 and the
standard deviation is 3.02. if a student is
selected at random, find the probability of
selecting a student whose score is
a. Between 24 and 35?
b. Between 33 and 37?
c. Greater than 34?
d. Less than 37?

9. SOLUTIONS:
STEP 1: Standardize the given
observation using the formula.
Z =
𝑥 − µ
𝛿
STEP 2: Find the area of the standardized
score using the areas under the normal
curve.

11. STEP 3: Draw the curve and write the z-value
along the horizontal line to where it should
belong. Positive written to the right side of 0
and negative value is written to left side of 0.
shade the corresponding area.
STEP 4: Calculate the area. The shaded
region serves as our guide on what we are
going to do with the areas corresponding to
their respective z-value.

12. Z-values Rules
1. The z-values are POSITIVE
and NEGATIVE
ADD the areas of the
corresponding z values
2. Both z-values are POSITIVE
or Both z-values are NEGATIVE
In either case, SUBTRACT the
smaller area from the bigger
area.
3. To the right of a POSITIVE z-
value or to the left of a
NEGATIVE z-value
SUBTRACT the area from 0.5
4. To the right of a NEGATIVE z
value or to the left of a
POSITIVE z-value
ADD area to 0.5

13. THANK YOU!
REFERENCE:
Pagala, R. 2008; Statistics.
Mindshapers Co., Inc.