At what age do babies learn to crawl Does it take longer to

At what age do babies learn to crawl? Does it take longer to learn in the winter when babies are bundled in clothes to restrict their movement? Data was collected from parents who brought their babies to NYU Infant Study Center to participate in one of a number of experiments between 1988 and 1991. Parents reported ages (in weeks) at which their child was first able to crawl a distance of four feet within one minute. The researchers also recorded the average outdoor temperature (in F) 6 months after the babies, date of birth. The resulting data was grouped together. If you fit the least-squares line to the 12 data points (one for each month) you obtain the following results from a software package. Notice that the temperature given is taken as the explanatory variable and crawling age as the response variable.

Dependant variable is the average crawling age

R squared = 49.0%

S = 1,319 with 12?2= 10 degrees of freedom

What is the appropriate slope of the least- squares regression line?

A) 35.68

B) 1.32

C) 0.01

D) -0.08

E) -0.58

Show your work.

Solution

The value at intersection of Temperature and coefficient is slope. Therefore, Slope = -0.077739 or -0.08.