T-test and Analysis of Variance abbreviated as ANOVA, are two parametric statistical techniques used to test the hypothesis. As these are based on the common assumption like the population from which sample is drawn should be normally distributed, homogeneity of variance, random sampling of data, independence of observations, measurement of the dependent variable on the ratio or interval level, people often misinterpret these two.
But there is a thin line of demarcation amidst t-test and ANOVA, i.e. when the population means of only two groups is to be compared, the t-test is used, but when means of more than two groups are to be compared, ANOVA is used. Here, is an article presented for you to understand the significant difference between t-test and ANOVA, have a look.
Content: T-test Vs ANOVA
|Basis for Comparison||T-test||ANOVA|
|Meaning||T-test is a hypothesis test that is used to compare the means of two samples.||ANOVA is a statistical technique that is used to compare the means of more than two samples.|
|Test statistic||(x ̄-µ)/(s/√n)||Between Sample Variance/Within Sample Variance|
Definition of T-test
The t-test is described as the statistical test that examines whether the population means of two samples greatly differ from one another, using t-distribution which is used when the standard deviation is not known, and the sample size is small. It is a tool to analyse whether the two samples are drawn from the same population.
The test is based on t-statistic, which assumes that variable is normally distributed (symmetric bell-shaped distribution) and mean is known and population variance is calculated from the sample.
In t-test null hypothesis takes the form of H0: µ(x) = µ(y) against alternative hypothesis H1: µ(x) ≠ µ(y), wherein µ(x) and µ(y) represents the population means. The degree of freedom of t-test is n1 + n2 – 2
Definition of ANOVA
Analysis of Variance (ANOVA) is a statistical method, commonly used in all those situations where a comparison is to be made between more than two population means like the yield of the crop from multiple seed varieties. It is a vital tool of analysis for the researcher that enables him to conduct test simultaneously. When we use ANOVA, it is assumed that the sample is drawn from the normally distributed population and the population variance is equal.
In ANOVA, the total amount of variation in a dataset is split into two types, i.e. the amount allocated to chance and amount assigned to particular causes. Its basic principle is to test the variances among population means by assessing the amount of variation within group items, proportionate to the amount of variation between groups. Within the sample, the variance is because of the random unexplained disturbance whereas different treatment may cause between sample variance.
Key Differences Between T-test and ANOVA
The significant differences between T-test and ANOVA are discussed in detail in the following points:
After reviewing the above points, it can be said that t-test is a special type of ANOVA that can be used when we have only two samples to compare their means. Although the chances of errors might increase if t-test is used when we have to compare more than two means of the samples concurrently, that is why ANOVA is used