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Education

Education

Education

Education

Education

Education

## Description

PARAMETRIC TEST

t-TEST (SAMPLE, POOLED OR UNPAIRED AND PAIRED)

ANOVA (ONE WAY ANOVA AND TWO WAY ANOVA)

T-TEST

• The t-test assesses whether the means of two groups are statistically different from each other.

Merits:

• It reduces the possibility of guessing the correct answer.

• It covers greater amount of contents than matching types test.

Demerits

• It is only appropriate for questions that can be answered by short responses.

• There is a difficult in scoring when the questions are not prepared properly and clearly.

1.717

F tabulated value 3.11

1.703

ANALYSIS OF

VARIANCE (ANOVA)

ANOVA (ONE WAY ANOVA AND TWO WAY ANOVA)

WHY ANOVA?

• Professor R.A. Fisher was the first man to use the term ‘Variance’* and, in fact, it was he who

developed a very elaborate theory concerning ANOVA, explaining its usefulness in practical

field.

• The ANOVA technique is important in the context of all those situations where we want to

compare more than two populations such as in comparing the yield of crop from several varieties

of seeds, the gasoline mileage of four automobiles, the smoking habits of five groups of

university students and so on.

• In such circumstances one generally does not want to consider all possible combinations of two

populations at a time for that would require a great number of tests before we would be able to

arrive at a decision. This would also consume lot of time and money, and even then certain

relationships may be left unidentified (particularly the interaction effects).

• Therefore, one quite often utilizes the ANOVA technique and through it investigates the

differences among the means of all the populations simultaneously.

One Way ANOVA

EXAMPLE

• Set up an analysis of variance table for the following per acre

production data for three varieties of wheat, each grown on 4 plots

and state if the variety differences are significant.

TWO Way ANOVA

Example

We find that differences concerning varieties of seeds are insignificant at 5% level as

the calculated F-ratio of 4 is less than the table value of 5.14, but the variety

differences concerning fertilizers are significant as the calculated F-ratio of 6 is more

than its table value of 4.76.

F(2,12) 3.89