Webers law a concept taught in most Introduction to Psycholo

Weber\'s law, a concept taught in most Introduction to Psychology courses, states that the ratio of the intensity of a stimulus to the \"just noticeable\" increment in intensity is constant, that is, the ratio doesn\'t depend on the intensity of the stimulus. The ratio is called the \"Weber fraction,\" so a concise statement of Weber\'s law is that \"the Weber fraction is constant, regardless of the stimulus intensity.\" It turns out that Weber\'s law is not so much a law as it is a rule of thumb, since it is violated in many situations. For instance, for some auditory stimuli, the Weber fraction does depend systematically on the stimulus intensity.

-0.45

1. Fill in the blank: For these data, stimulus intensities that are greater than the mean of the stimulus intensities tend to be paired with Weber fractions that are _____ the mean of the Weber fractions.

Choose one

greater than

less than

2. Fill in the blank: According to the regression equation, for an increase of one decibel in stimulus intensity, there is a corresponding _____ of 0.0852 decibels in the Weber fraction.

Choose one

increase

decrease

3. From the regression equation, what is the predicted Weber fraction (in decibels) when the stimulus intensity is 70 decibels?_____________ (Round your answer to at least two decimal places.)

4. What was the observed Weber fraction (in decibels) when the stimulus intensity was 70 decibels?__________

Solution

Here,

y^ = 2.6412 - 0.0852x

Hence, the slope, B1 = -0.0852, is negative.

********************

1.

As the slope is negative, greater values of x tend to be paired with LOWER values of y.

Thus, the answer is LESS THAN. [ANSWER]

******************

2.

As the slope is negative, then it is a DECREASE. [ANSWER]

***********************

3.

Thus, the regression line is              
              
y^ =    -0.0852   x   +   2.6412
              
Thus, if x =    70          
              
Then              
              
y^ =    -3.3228   [ANSWER]

**********************

4. Looking at the table, it is -3.06. [ANSWER]