We do this by comparing the value r to an entry in Table 4-6. The value of a in the table gives us the probability of concluding that r ? 0 when, in fact, r 5 0 and there is no population correlation.

We have two choices for a: a 5 0.05 or a 5 0.01.

(a) Look at Problem 13 regarding the variables x 5 age of a Shetland pony and y 5 weight of that pony. Is the value of r large enough to conclude that weight and age of Shetland ponies are correlated? Use a 5 0.05.

(b) Look at Problem 15 regarding the variables x 5 lowest barometric pressure as a cyclone approaches and y 5 maximum wind speed of the cyclone. Is the value of r large enough to conclude that lowest barometric pressure and wind speed of a cyclone are correlated? Use a 5 0.01.