I'm testing the residuals of a linear regression using **Breusch-Pagan** Test to detect Heteroscedasticity.

This is the plot of the residuals:
![Residuals](https://i.stack.imgur.com/28sNL.jpg)

and this is the R code:

```
> library(lmtest)
> 
> mod <- lm(rnorm(1000)~1)
> 
> bptest(mod)

    studentized Breusch-Pagan test

data:  mod 
BP = 0, df = 0, p-value < 2.2e-16

```

Could someone tell me why it rejects the null hypothesis of homoscedastic errors?

The plot doesn't look heteroscedastic.

**EDIT:**

However the plot is an example, I have two list of prices (**priceA** and **priceB**), I need to check if the residuals generated by a linear regression of these two list: lm(priceA ~ priceB + 0) I need zero intercept are homescedastic or not. Could someone give me a small example? The length of each price list is 750.

**EDIT:**

I also get: 

BP = 67.4362, df = 1, p-value < 2.2e-16

with this chart
![new charts](https://i.stack.imgur.com/vKe1G.png)

Does it be homoscedastic? I have plotted the residuals.

**@Wolfgang**, I get this result following the example you posted.

```
> summary(mod)$r.squared * 750
[1] 681.0114

```