Descriptive Statistics
Prepared by:
Asma Qassim Al-jawarneh
Ati Sardarinejad
Reem Suliman
Dr. Balakrishnan Muniandy
PTPM-USM
What Is Statistics?

Statistics is a collection of tools used for
converting raw data into information to help
decision makers in their works.

Descriptive statistics are numerical estimates
that organize and sum up or present the data.

Inferential statistics is the process of inferring
from a sample to the population.
Descriptive
Statistics
Concept & definition

Describing data with tables and graphs like;
frequency polygon, pie chart.

Mathematical methods (such as mean,
median, standard deviation) that summarize
and interpret some of the properties of a set
of data (sample) but do not infer the
properties of the population from which the
sample was drawn.
Concept & definition (cond.)

Descriptive statistics aim to describe the
midpoint of a spread of scores, usually
referred to as the measure of central
tendency, and the spread of scores known as
the dispersion or variance.
Descriptive Measures

Central Tendency measures. They are computed to give
a “center” around which the measurements in the data
are distributed.
1. Mean: Sum of the values divided by the number of cases
ex. : 2,4,6,8
Mean=(2+4+6+8)/4=5
2. Median: represents the middle of the ordered sample data
ex. : 1,2,3,4,5
Median= 3
ex. : 1,3,4,6,9,12,16,19
Median= (6+9)/2= 7.5
3. Mode: is the value that occurs most frequently
ex. 3,4,5,5,6,8,9,9,9
Mode= 9
Descriptive Measures (cond.)

Variation or Variability
measures.
indices enabling the
researcher to indicate how
spread out a group of scores
are.
1. Range: the difference
between the highest and
lowest score in a
distribution.
Range= 60-32=28
Descriptive Measures (cond.)
2. variation (s2 )is
the sum of the
squared deviations
from the mean
divided by the
number of cases
minus 1.
3. Standard
deviation (s) is the
square root of the
variance.
When use DS

When you describe your databases or the relationships
between your variables.

when a researcher wants to gain a better understanding of
a topic.

The idea behind this type of research is to study
frequencies, averages, and other statistical calculations.

In medical and nursing situations.
Use in statistical analyses

Descriptive statistics provide simple summaries about the sample
and the measures.
ex.: the grade point average for many students.
This single number describes the general performance of a student
across the range of their course experiences.
- The percentage summarizes or describes multiple discrete
events.

Describing a large set of observations with a single indicator risks
distorting the original data or losing important detail.
the GPA doesn't tell you whether the student was in difficult or
easy courses.

Despite these limitations, descriptive statistics provide a powerful
summary that may enable comparisons across people or other units
Research Article

Title: Nursing Students’ Reading and English Aptitudes
and Their Relationship to Discipline-Specific Formal
Writing Ability: A Descriptive Correlational Study.

Problem statement: writing apprehension is a common
phenomenon among nursing students.

Purpose of the study: to describe writing apprehension
and to assess the relationships among reading and
English aptitude and discipline-specific formal writing
ability among undergraduate nursing students.
Research Article (cond.)

Sample: 146 sophomores nursing students.

Instruments: Test of Essential Academic Skills (TEAS).

Result:
- DESCRIPTION OF THE SAMPLE The sample consisted of
146 sophomore nursing students from two admission cohorts.
Each cohort was comprised of 73 students. Three students (2
percent) had English as their second language.
- Descriptive statistics were calculated regarding reading and
English aptitudes. Reading aptitudes (M = 89.7) were higher
than English aptitudes (M = 80.6).
Research Article (cond.)
Research Article (cond.)

Results:
- The results indicated that undergraduate nursing students’
reading aptitudes were higher than their English aptitudes, and
that English aptitude was more predictive of formal writing ability
than was reading aptitude.
- TEAS English subtest addresses areas more directly related to
writing (e.g., punctuation, grammar, sentence structure, and
spelling) than does the reading subtest (e.g., paragraph
comprehension, passage comprehension,
inferences/conclusions).
Conclusion

Descriptive analyses are likely the most simple of
statistical analysis to perform and to interpret.

permit the researcher to describe many pieces of
data with a few indices

Descriptive statistics provide us with a useful strategy
for summarizing data and providing a description of
the sample but cannot provide information for causal
analysis. Analysis of data that allows us to generalize
from a sample to a larger population requires the use
of inferential statistics.
References



Fisher, M. J. and A. P. Marshall (2009).
Understanding descriptive statistics. Australian
Critical Care 22(2): 93-97.
Newton, S. and G. Moore (2010). Nursing Students'
Reading and English Aptitudes and Their
Relationship to Discipline-Specific Formal Writing
Ability: A Descriptive Correlational Study. Nursing
Education Perspectives 31(4): 221-225.
http://www.answers.com/topic/descriptivestatistics#ixzz1F2IvSG9a
Thank you