I'm doing a multivariate linear regression with R, and i find myself with the following residuals vs fitted plot:

As you can see there is a very regular line of points that seems to follow a precise pattern.

My questions are:

1. How do I interpret such a behavior, and what can I do to fix it?
2. Is there a way to isolate/extract those points? I'd like to take a look at them individually in my data set to see if by examining them I notice some patterns in the data.

I'm doing a multivariate linear regression with R, and i find myself with the following residuals vs fitted plot:

As you can see there is a very regular line of points that seems to follow a precise pattern.

My questions are:

1. How do I interpret such a behavior, and what can I do to fix it?
2. Is there a way to isolate/extract those points? I'd like to take a look at them individually in my data set to see if by examining them I notice some patterns in the data.

Additional info: My model is:

v.lm = lm(sqrt(v.stima$Y)~., data=v.stima)

Y is a count-variable (non-negative integer). I'm using sqrt because without it the plot has the typical "funnel" shape that indicates a non-homoscedastic error.

I'm doing a multivariate linear regression with R, and i find myself with the following residuals vs fitted plot:

As you can see there is a very regular line of points that seems to follow a precise pattern. My question is:

1. How do I interpret such a behavior, and what can I do to fix it?
2. Is there a way to isolate/extract those points? I'd like to take a look at them individually in my data set to see if by examining them I notice some patterns in the data.

Thanks in advance for any help you can give me.

I'm doing a multivariate linear regression with R, and i find myself with the following residuals vs fitted plot:

As you can see there is a very regular line of points that seems to follow a precise pattern.

My questions are:

1. How do I interpret such a behavior, and what can I do to fix it?
2. Is there a way to isolate/extract those points? I'd like to take a look at them individually in my data set to see if by examining them I notice some patterns in the data.