MS 150 Statistics Quiz 04 • Name:

The following data was inspired by the study Birth weight; postnatal, infant, and childhood growth; and obesity in young adulthood: evidence from the Barry Caerphilly Growth Study. Means and standard deviations were obtained for the mass in kilograms of nine month old female babies and these were used to generate values from a normal distribution with those parameters using WolframAlpha.com. Parameters for body mass index at about 25 years old were also used to generate values. Science uses mass in kilograms to measure weight.

Weight at nine months (kg)BMI at 25
8.0 15.6
8.7 22.6
9.0 22.7
9.0 22.9
9.0 23.7
9.3 24.0
10.0 24.3
10.5 25.8
11.3 27.4
11.6 31.6
  1. _________ Calculate the sample size n.
  2. ______________ Calculate the slope of the linear regression for the data.
  3. ______________ Calculate the y-intercept of the linear regression for the data.
  4. ______________ Is the relation between weight at nine months and the BMI at 25 years positive, negative, or neutral?
  5. ______________ Calculate the correlation coefficient r for the data.
  6. ______________ Is the correlation none, weak/low, moderate, strong/high, or perfect?
  7. ______________ Determine the coefficient of determination.
  8. ______________ What percent in the variation in the weight at nine months explains the variation in BMI?
  9. ______________ Using the slope and intercept and a weight at nine months of 8.4 kg, predict the BMI.
  10. ______________ Using the slope and intercept and a BMI of 29.5, predict what was the weight at nine months