1: At what age do babies learn to crawl? Does it take longer to learn in the winter when babies are often bundled in clothes that restrict their movement? Data were collected at the University of Denver Infant Study Center, where parents and their babies participated in one of a number of experiments between 1988 and 1991. Parents reported the age (in weeks) at which their child was first able to creep or crawl a distance of four feet within one minute. The researchers also recorded the average outdoor temperature (in °F) six months after each baby's birthdate. For each month of the year, the researchers selected one baby, at random, born in that month. If we fit the least-squares line to the 12 data points (one for each month) we obtain the following results from a software package. Notice that temperature is taken as the explanatory variable and crawling age as the response.
s = 1.319
Suppose we wish to predict the crawling age of a particular baby when the average outdoor temperature is 25°F six months after birth. We use computer software to do the prediction and obtain the following output.
A. (32.087, 35.382).
B. (30.364, 37.105).
C. 33.735 ± 0.739.
2. At what age do babies learn to crawl? Does it take longer to learn in the winter when babies are often bundled in clothes that restrict their movement? Data were collected at the University of Denver Infant Study Center, where parents and their babies participated in one of a number of experiments between 1988 and 1991. Parents reported the age (in weeks) at which their child was first able to creep or crawl a distance of four feet within one minute. The researchers also recorded the average outdoor temperature (in °F) six months after each baby's birthdate. For each month of the year, the researchers selected one baby, at random, born in that month. If we fit the least-squares line to the 12 data points (one for each month) we obtain the following results from a software package. Notice that temperature is taken as the explanatory variable and crawling age as the response.
s = 1.319
The quantity s = 1.319 is an estimate of the standard deviation of the deviations in the simple linear regression model. Based on this information, the sum of squares for error, SSE, is
A. 1.319.
B. 1.740.
C. 17.398.