Variables

Definition of variable: is a characteristic or attribute of a person or object (polit, 2004).

Example of some variables• Weight.• Body temperature.• Blood pressure reading.

• Stress level.

• Anxiety levelDr. Yousef Aljeesh

Types of variables

1- Continuous variables: variable can take on a range of different values. Their values can be presented on continuum.

Examples

. Age

. weight,

. height.

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2- Categorical variables: variables that take on a much smaller range of values.

Example: . Male or female. Pregnant / not pregnant .. Smoker / non-smoker.. HIV positive/ HIV negative.

. When the categorical variables take on only two values, they are sometimes referred to as dichotomous variables.

Some additional examples of categorical variables.. marital state (married, single, divorce, and widowed).

Dr. Yousef Aljeesh

3. Dependent variables: the outcome variable of

interest (effect). The dependent variable usually is

the variable the researcher is interested in

understanding, explaining or predicting.

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4- Independent variable: the variable that is believed to cause or influence the dependent variable. In the experimental research the independent variable is the variable that is manipulated.

Note: the presumed cause is referred to as the independent

Example: the extent to which lung cancer (dependent variable) Depends on smoking behavior (independent variable).

Dr. Yousef Aljeesh

5. Extraneous variable: variable that confounds the

relationship between independent variable and

dependent variable that needs to be controlled either

in the research design or through statistical

procedure.

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6. Homogenous variable: the degree to which objects or variables are similar characteristic.

7- Heterogeneous variable: the degree to which objects or variables are dissimilar characteristic

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Example of independent (IDV) and dependent variables (DV)

1- Do physician administer greater amount of

narcotic drug to men than women.

DV IDV

Amount of narcotic Gender

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2- what is the effect of activity and bed rest on weight reduction among Gestational diabetes women.

DV IDV

Weight reduction Activity& rest

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3- Is adherence to therapeutic regime decrease

the incidence of PIH.

DV IDV

Incidence of PIH Adherence of therapeutic regime

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Hypotheses

Definition of hypothesis : It is a statement of predicted relationship between two or more than two variables.

Note: The difference between problem statement and hypothesis is that Hypothesis translate problem statements into predictions of expected outcomes.

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Types of Hypotheses

1. Simple Hypothesis : A hypothesis that predicts the relationship between one dependent variable (DV) and one independent variable (IDV). It is easy to test and analyze it.

Example

There is a relationship between smoking and development of stroke among hypertensive patients in Gaza strip.

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2. Complex hypothesis: (Multivariate hypothesis) : A hypothesis that predicts the relationship between

two or more dependent variables and two or more independent variables.

Example: There is a relationship between high fat diet and

smoking and development of atherosclerosis and stroke among hypertensive patients in Gaza strip.

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3. Directional hypothesis: is one that specifies the expected direction of the relationship between variables. The researcher predicts not only the existence of a relationship but also the nature of the relationship.

The key word of directional hypothesis is

(less, more, greater, lower, higher, positive, negative)

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Example

1. Hypertensive smoker's patients are more

likely to develop stroke than hypertensive

non-smoker's patients.

2. Older midwives are less likely to express approval of the expanding roles than

younger midwives.

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4. Statistical hypothesis (Null hypothesis): is one

that stated there is no relationship between

variables.

Example

1. Hypertensive smoker's patients are likely to develop

stroke as hypertensive non-smoker's patients.

2. Older midwives are likely to express approval of the expanding roles as younger physiotherapist.

Dr. Yousef Aljeesh

Hypothesis criteria

The hypothesis should includes

1. Population

2. Variables

3. Reflect the problem statement

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Exercise

Look at the following hypotheses, and write down what are the two variables, statement of purpose, and null hypothesis.

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1. Men and women with arthritis differ in their responsiveness to heat treatment.

(Hypothesis)

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Independent variable: sex (male or female)

Dependent variable: responsiveness to

heat treatment

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• Problem statement

a. Statement of purpose: The purpose of this study is to explain the relationship between men and women and their responsiveness to heat treatment among patients with arthritis.

b. Research question: what is the relationship between men and women and their responsiveness to heat treatment among patients with arthritis.

Dr. Yousef Aljeesh

2. There is a difference in professional competence between midwives who trained in hospital-based training schools than those who trained in polytechnic-based training schools

(Hypothesis)

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Independent variable: Type of training establishment

(hospital-based or polytechnic-based)

Dependent variable: professional competence

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• Problem statement

a. Statement of purpose: The purpose of this study is to compare between Type of training establishment (hospital-based or polytechnic-based) and professional competence among midwives.

b. Research question: Are there a relationship between Type of training establishment (hospital-based or polytechnic-based) and professional competence among midwives.

Dr. Yousef Aljeesh

Statistical hypothesis (Null hypothesis)

There is no relationship between Type of training

establishment (hospital-based or polytechnic-based)

and professional competence among midwives.

Dr. Yousef Aljeesh