Chicken farming is a multi-billion dollar industry, and any methods that increase the growth rate of young chicks can reduce consumer costs while increasing company profits, possibly by millions of dollars. An experiment was conducted to measure and compare the effectiveness of various feed supplements on the growth rate of chickens. Newly hatched chicks were randomly allocated into six groups, and each group was given a different feed supplement.

Please calculate summary statistics (mean, variation) from this data set along with box plots showing the distribution of weights by feed type.

Describe the distributions of weights of chickens that were fed linseed and horsebean.

Do these data provide strong evidence that the average weights of chickens that were fed linseed and horsebean are different? Use a 5% significance level.

Casein is a common weight gain supplement for humans. Does it have an effect on chickens? Using data provided, test the hypothesis that the average weight of chickens that were fed casein is different than the average weight of chickens that were fed soybean. If your hypothesis test yields a statistically significant result, discuss whether or not the higher average weight of chickens can be attributed to the casein diet. Assume that conditions for inference are satisfied.

In the above exercises, 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 can be used to test for differences between the average weights of chicks on different diets. Conduct a hypothesis test to determine if these data provide convincing evidence that the average weight of chicks varies across some (or all) groups.

weight feed
179 horsebean
160 horsebean
136 horsebean
227 horsebean
217 horsebean
168 horsebean
108 horsebean
124 horsebean
143 horsebean
140 horsebean
309 linseed
229 linseed
181 linseed
141 linseed
260 linseed
203 linseed
148 linseed
169 linseed
213 linseed
257 linseed
244 linseed
271 linseed
243 soybean
230 soybean
248 soybean
327 soybean
329 soybean
250 soybean
193 soybean
271 soybean
316 soybean
267 soybean
199 soybean
171 soybean
158 soybean
248 soybean
423 sunflower
340 sunflower
392 sunflower
339 sunflower
341 sunflower
226 sunflower
320 sunflower
295 sunflower
334 sunflower
322 sunflower
297 sunflower
318 sunflower
325 meatmeal
257 meatmeal
303 meatmeal
315 meatmeal
380 meatmeal
153 meatmeal
263 meatmeal
242 meatmeal
206 meatmeal
344 meatmeal
258 meatmeal
368 casein
390 casein
379 casein
260 casein
404 casein
318 casein
352 casein
359 casein
216 casein
222 casein
283 casein
332 casein