Question

7.37 Chicken diet and weight, Part IlII. In Exercises 7.27 and 7.29 we compared the effects of two types of feed at a time. A better analysis would first consider all feed types at once: casein, horsebean, linseed, meat meal, soybean, and sunflower. The ANOVA output below can be used to test for differences between the average weights of chicks on different diets. Sum Sq Mean Sq F value Pr(>F) 5 231,129.16 46,225.83 65 195,556.02 3,008.55 Df feed 0.0000 15.36 Residuals Conduct a hypothesis test to determine if these data provide convincing evidence that the average weight of chicks varies across some (or all) groups. Make sure to check relevant conditions. Figures and summary statistics are shown below. 400 350- Mean 323.58 160.20 218.75 276.91 SD n 300- 64.43 casein 12 horsebean 38.63 10 250- linseed 52.24 12 meatmeal 64.90 11 200- soybean 246.43 54.13 14 sunflower 328.92 48.84 12 150- 100- casein horsebean linseed meatmeal soybean sunflower Weight (in grams) HIH

Answer 1

Since the conditions for normality is satisfied by the boxplot shown in the table, we can conduct ANOVA test.

Let us consider H0: the average weight of chiks is same across all the groups.

And H1 :the average weight is not same among all the groups.

From the anova output shown, F value = 15.36

And p value is 0.000

Since p value is less than 0.05 , we should reject H0 and conclude that the average weight of chicks varies across all the groups.