In: Statistics and Probability
A researcher found that age (X) and annual income (Y) were correlated with r = 0.50. For age, M = 50 and SD = 10. For annual income (in thousands of dollars), M = 60 and SD = 10. The intercept of the regression line was found to be 35. What is the value of the slope of the regression line?
## Q ) A researcher found that age (X) and annual income (Y) were correlated with r = 0.50. For age, M = 50 and SD = 10. For annual income (in thousands of dollars), M = 60 and SD = 10. The intercept of the regression line was found to be 35. What is the value of the slope of the regression line?
Answer : Here independent variable : age = x
and dependent variable : annual income = y
r : correlation coefficient between x and y = 0.50
for age : mean and standard deviaton are : xbar = M = 50 and Standard deviation = SD (x) = 10
and for annual income : mean and standard deviation are : ybar = M = 60 and standard deviation = SD(y) = 10
here y intercept value = 35
we have to find out slope value :
formula for slope : = r * (SD(y) / SD(x) )
= 0.50 * ( 10 /10 )
= 0.50
slope is 0.50
## note : Where r is the correlation between x and y and SD(x) and SD(y) are the standard deviations of the x values and the y values , respectively , we can simply divide SD(y) by SD(x) and multiply the resuly by r we can get slope value