Investigate the relationship between crying and IQ

Infants who cry easily may be more easily stimulated than others. This may be a sign of higher IQ. Child development researchers explored the relationship between the crying of infants four to ten days old and their later IQ test scores. The researchers recorded the crying of babies and measured its intensity by the number of peaks in the most active 20 seconds. They later measured the children’s IQ at age three years using the Stanford-Binet IQ test. The follow table contains data on 10 infants (the sample size reduced for this homework). Do children with higher crying counts tend to have higher IQ?

NOTE: use all columns to calculate components of regression and correlation. Add column if is needed

a. Find the mean of each independent and dependent variable

b. Obtain the slope **(b**) and the y-intercept (**a**) of the least square regression. Describe what is **b** and what is **a ** in this least square regression equation.

c. Write the regression equation for the crying (Y) and IQ (X)

d. Predict the intensity of crying if the child IQ would be 112

e. Calculate the correlation between crying and IQ

f. Calculate R2. What does R2 tell us about the relationship between the independent and dependent variables