Question

Oh, that smarts! Infants who cry easily may be more easily stimulated than others. This may be a sign of a higher IQ. Child development researchers explored the relationship between the crying of infants 4 to 10 days old and their IQ test scores at age $3$ years. A snap of a rubber band on the sole of the foot caused the infants to cry. The researchers recorded the crying and measured its intensity by the number of peaks in the most active $20$ seconds. The correlation for these data is $r=0.45.16$ Interpret the correlation.

Short answer

There is a weak and positive association between the count of crying peaks and $IQ$ at age $3$ years.

Step-by-step solution

Given information

Correlation, $r=0.45$

Explanation

A positive linear correlation exists when $r$ is positive.

A negative linear correlation exists when $r$ is negative.

For weak correlation,

For moderate correlation,

For strong correlation,

Note that

The association between the crying of infants $4$ to $10$ days old and their IQ test scores at the age of $3$ years is a weak and positive association.