Albert, a student researcher, varies the amount of food given to rats in an experiment to measure the effect on their learning behavior. In albert's study, the amount of food given is the independent variable.
An independent variable is under the control of the experimenter. Independent variable does not depend on the other variables involved in the experiment. Since the amount of food is varied, it is not depending on other variables like size of mice, weight, etc. 
 
        
             
        
        
        
Answer: I believe the answer is C. Contractions are informal
Explanation:
 
        
             
        
        
        
The regression equation is:
y = 1.15 – 0.251 x₁ + 0.078 x₂ + 0.306 x₁x₂
<span>
 <span>
 <span>
 Where,
x₁ = -0.2508
x₂ = 0.0777
x₁x₂ = 0.3058
Inserting the values,
<span>
<span>
</span></span>y = 1.15 – {0.251 × (-0.2508)} + {0.078 ×(0.0777)} + {0.306 × (0.3058)}
</span></span></span>
y = 1.15 - (- 0.0629508) + 0.0060606 + 0.935748
y = 1.15 + 0.0629508 + 0.0060606 + 0.935748
y = 1.3125862
Answer:
x₁ and x₂ are main effects (a type of tuna and type of packing liquid) that contribute significant information for the prediction of <span>y.</span>
 
        
             
        
        
        
Answer:The answer is c
Explanation: The mean is usually a good choice to represent a whole data set as a single number.
Mean is derived by adding a whole data and dividing the data by the number of points. It can also be referred to as the average that is used to derive the central tendency of data. It also measures the central tendency in a data set. It can be called an average.