Question

The experimenter is interested in the number of errors made by rats in a maze as a function of the kind of reward they are given. Group 1 receives 100% water reward; Group 2 receives a sugar solution; and Group 3 receives beer. Perform an ANOVA to determine if the difference among groups is likely to be statistically significant? Perform t-tests. Which groups have significantly different means at the .05 level of significance?

Group          1                   2                   3

                     4                   13                 26

                     5                   15                 21

                     3                   12                 19

                     9                   15                 21

                     6                   15                 23

                     5                   16                 24

                     7                   14                 19

Answer 1

Solution:-

State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.

Null hypothesis: u₁ = u₂ = u₃

Alternative hypothesis: At-least one of the u is not equal.

Formulate an analysis plan. For this analysis, the significance level is 0.05.

Analyze sample data.

F statistics is given by:-

F = 110.109

F_critical = 3.55

The P-value = less than 0.0001.

Interpret results. Since the P-value (almost 0) is less than the significance level (0.05), we have to reject the null hypothesis.

Conclusion:-

Reject H₀, There is sufficient evidence for significant differences between the three kinds.