Question

For each of the following pairs of variables, indicate whether you would expect a positive correlation, a negative correlation, or little or no correlation. For the ones which are correlated, is the relationship causal? If so, which one causes (or at least influences) the other? If not, suggest a third variable which might be related to both.

a:The number of cavities in elementary school children and their vocabulary size.

b:The number of fire engines at each fire and the damage done in dollars.

c:The number of body lice on New Hebrides Islanders and their white cell count.

d:The death rate due to cancer in various countries and the average amount of fat in the diet.

f:The salaries of Presbyterian ministers in Massachusetts and the price of cigars in Santo Domingo.

Answer 1

a) No correlation between number cavity and vocabulary size.

   the number of books read and vocabulary size is positively correlated.

b) Negatively correlated, As the number of fire engines increases ,the damge done decreases.

c)no relation ,Personal hygiene and number of body lice are correlated.

d) positively correlated, increase in the amount of fat in diet may increase the chance of cancer.

e) no relation. production of cigars and its price related.