Recall Exercise 6.2.37 on inhibitory control. Besides keeping track of the total time it took the animals to reach the food, the researchers also kept track of the amount of time the animals spent at the fence close to the food. These results are found in the file InhibitoryControl-2. Put the data into the Multiple Means applet and answer (a)–(d). 

a. State the hypotheses either in words or using appropriate symbols. 

b. What are the two sample means? 

c. Find an approximate p-value. Based on your p-value, do you have strong evidence that pack dogs and wolves spend different amounts of time at the fence close to the food, on average? 

d. Find a 2SD confidence interval for the difference in the amount of time the animals spend at the fence close to the food (dogs’ times – wolves’ times). Do the results of the confidence interval back up your conclusion from part (c)? Explain.

Data from  Exercise 6.2.37

Researchers Marshall-Pescini et al. (2015) compared identically raised pack dogs and wolves on inhibitory control. To do this, a v-shaped fence constructed of wire mesh was set up with a food item (a dead, one-day-old chick) placed so the animal could see it inside the fence at the corner. Animals showing inhibitory control would move quickly around the fence to get the food and not get distracted and spend time looking at it through the fence. Is there a difference in inhibitory control between pack dogs and wolves, that is, do they get to the food at different rates? The time, in seconds, it took the animals to reach the food for this test are found in the file InhibitoryControl-1. Put the data into the Multiple Means applet and answer (a)–(e).