Consider this study: A New York Times article published on April 24, 2007, reported the research of Dr. Giorgio Vallortigara, a neuroscientist at the University of Trieste, Italy, and his two colleagues. The researchers asked whether a dog wags its tail in a preferred direction in response to positive stimuli and in another direction in response to negative stimuli. To answer their question, they recruited 30 dogs that were family pets. Filming each dog from above, they allowed it to view (through a slat in its cage) three positive stimuli separately, in order of descending positivity: its owner, an unfamiliar human, and a cat. All the dogs responded by wagging their tails to the right. But when the dogs were presented with an unfamiliar, aggressive dog, a negative stimulus, all dogs wagged their tails to the left. Which of the following statements is the research hypothesis for this study?

a. A dog's tail will wag differently in response to positive stimuli and to negative stimuli. b. A dog's tail will wag more to the left in response to positive stimuli and more to the right in response to negative stimuli. c. A dog's tail will wag more to the right in response to positive stimuli and more to the left in response to negative stimuli. d. There will be no difference in a dog's tail wagging while viewing positive and negative stimuli.

a. A dog's tail will wag differently in response to positive stimuli and to negative stimuli.

Step-by-step explanation:

A research hypothesis is a proposition that can be tested about the possible outcome of a study based on different stimuli.

A research hypothesis is a specific, clear, and testable proposition or predictive statement about the possible outcome of a scientific research study based on a particular property of a population, such as presumed differences between groups on a particular variable or relationships between variables.

Before a quantitative study takes place, it is important to state the research hypothesis because it is very important to the study.

There is usually an expectation or predicted outcome of the study because the research is determined by the hypothesis.

So it was already hypothesised that a dog would wag its tail in a preferred direction when it is faced with negative or positive stimuli. So the hypothesis was tested as different sets of dogs were placed in a cage and introduced to different stimuli.

From the observation of the researchers, all the dogs wagged their tails to the right when they saw a familiar face (positive stimuli) and wagged their tails to the left when they faced an aggressive dog (negative stimuli)

answer: expected value of x = 1.0

step-by-step explanation:

p(x=0) = 0.25

p(x=1) = 0.50

p(x=2) = 0.25

expected value for x = 0×0.25 + 1×0.5 + 2×0.25 = 1.0