Question

Answer each question using essay format (that is, use sentences and paragraphs, not point form). For each question, answers are limited to a maximum of 150-200 words.

1. What is ANOVA?

Answer 1

1. What is ANOVA?

ANOVA stands for “Analysis of Variance ”. The simplest kind of ANOVA. ANOVA which involves a single categorical variable called a factor with k values, known as its levels and a single numerical response. The question of interest is whether the mean value of the response is the same at all levels of the factor (the null hypothesis) or whether it differs by factor level (the alternative).The assumptions to be checked before performing ANOVA are

• Independence of cases – this is an assumption of the model that simplifies the statistical analysis.
• Normality – the distributions of the residuals are normal.
• Equality (or "homogeneity") of variances, called homoscedasticity...

Consider an example with four independent groups and a continuous outcome measure. The independent groups might be defined by a particular characteristic of the participants such as BMI (e.g., underweight, normal weight, overweight, obese) or by the investigator (e.g., randomizing participants to one of four competing treatments, call them A, B, C and D). Suppose that the outcome is systolic blood pressure, and we wish to test whether there is a statistically significant difference in mean systolic blood pressures among the four groups.