Question

• A researcher measures the relationship between the number of interruptions during a class and time spent "on task" (in minutes). Answer the following questions based on the results provided.

  Number of Interruptions	Time Spent "On Task"
  11	18
  5	37
  9	18
  4	31

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• 
  

• Part (a)

  Compute the Pearson correlation coefficient. (Round your answer to three decimal places.)
  

• Part (b)

  Multiply each measurement of interruptions times 3 and recalculate the correlation coefficient. (Round your answer to three decimal places.)
  

• Part (c)

  Divide each measurement in half for time spent "on task" and recalculate the correlation coefficient. (Round your answer to three decimal places.)
  

• Part (d)

  True or false: Multiplying or dividing a positive constant by one set of scores (X or Y) does not change the correlation coefficient. Note: Use your answers in (a) to (c) to answer true or false.

  True False   

Answer 1

A)

If Number of interruptions are denoted by x and time spent on task by y then

We know that pearson correlation is calculated by:

where

B)

After multiplying x by 3 and then corrrelation coefficient is same as  -0.8973007

C)

After dividing the y by 2 also we get same correlation as  -0.8973007

D)

Yes multiplying and dividing x or y by a constant doesnot changes its correlation.

Above calculations are done in R

Code along with output is attached herewith.