Various Authors• “A hypothesis is a conjectural statement of the

relation between two or more variables”. (Kerlinger, 1956)

• “Hypotheses are single tentative guesses, good hunches – assumed for use in devising theory or planning experiments intended to be given a direct experimental test when possible”. (Eric Rogers, 1966)

• “Hypothesis is a formal statement that presents the expected relationship between an independent and dependent variable.”(Creswell, 1994)

• A hypothesis is a logical supposition, a reasonable guess, an educated conjecture. It provides a tentative explanation for a phenomenon under investigation." (Leedy and Ormrod, 2001).

Hypothesis Theory Fact

• A specific, testable prediction about what is expected to happen in a study

•makes a specific prediction about a specified set of circumstances

•a speculative guess that has yet to be tested

•is new and relatively untested

•the probability of error and correction are high

• Well-established principle which predicts events in general terms • Arises from repeated observation and testing

•Incorporates facts, laws, predictions, and tested hypotheses that are widely accepted

•extensively tested and is generally accepted

•is something which is assumed to be true

•once a theory has been confirmed and reconfirmed over and over again, we get to the point that it will be treated as a "fact"

•doesn't mean 'absolute certainty

One common feature for facts, theories, and hypotheses in science is that they are all treated as fallible — the likelihood of error might vary greatly, but they are still regarded as something less than absolute truth.

A Hypothesis• must make a prediction• must identify at least two variables• should have an elucidating power• should strive to furnish an acceptable

explanation or accounting of a fact• must be falsifiable meaning hypotheses must

be capable of being refuted based on the results of the study

• must be formulated in simple, understandable terms

• should correspond with existing knowledge• In general, a hypothesis needs to be

unambiguous, specific, quantifiable, testable and generalizable.

STATISTICAL HYPOTHESISA statistical hypothesis is an assertion regarding the statistical distribution of thepopulation. It is a statement regarding the parameters of the populationStatistical hypothesis is denoted by H

Examples:1. H: The population has mean μ = 252. H: The population is normally distributed with mean μ=25 and standard deviationIn a test procedure, to start with, a hypothesis is made. The validity of this hypothesis is tested. If the hypothesis is found to be true, it is accepted. On the other hand, if it is found to be untrue, it is rejected

The hypothesis which is being tested for possible rejection is called null hypothesis.

The null hypothesis is denoted by H0. Hypothesis which is accepted when the nullhypothesis is rejected is called alternative hypothesis. The alternative hypothesis is denoted by H1

CRITICAL REGION• From a population many samples of the same size n can be drawn.

Let S be the set of all such sample of size n that can be drawn from the population.

• Then, S is called sample space. While testing a null hypothesis, among the samples which belong to S, some samples lead to the acceptance of the null hypothesis, whereas, some others lead to the rejection of the null hypothesis.

• The set of all those samples belonging to the sample space which lead to the rejection of the null hypothesis is called critical region.

• The critical region ids denoted by ω. The critical region is also rejection region. The set of samples which lead to the acceptance of the null hypothesis is the acceptance region. It is (S- ω).