I am running a multi-linear regression in R. And I want to add 3 to all the rows for column named "educ", then find out the 99% confidence interval for this predicted change. here are my codes:
reg5 = lm(sleep ~ educ + age + gdhlth + smsa + union + selfe +
marr + yrsmarr + yngkid, data = data)
newdata = data
newdata$educ = newdata$educ + 3
keeps <- c('educ', 'age', 'gdhlth','smsa', 'union','selfe' ,
'marr', 'yrsmarr','yngkid')
newdata = newdata[keeps]
predict(reg5, newdata = newdata, interval = 'prediction', level=0.99)
And my results are having over 300 rows enter image description here Can anyone help to look at why I can't get a simple confidence interval?
