Question: Consider the following bootstrap:

```
library(MASS)
library(boot)

# c)
set.seed(1)
boot.fn= function(data, index) mean(data[index])
output=boot(Boston$medv, boot.fn, 1000)

```

If we run `print(output)`, we get 

```
Call:
boot(data = Boston$medv, statistic = boot.fn, R = 1000)

Bootstrap Statistics :
    original      bias    std. error
t1* 22.53281 0.008517589   0.4119374

```

However, when I examine the `output` object, I cannot find values representing the bootstrap statistics. Where is `original`, `bias` and `std. error` in the actual `output` object returned by boot?

Answer: 
They are calculated by `print.boot` and not stored in the `boot` object. Look at `getAnywhere(print.boot)` for the details.

You can either calculate these values yourself or use `capture.output`.

For your example:

```
#original:
output$t0
#bias:
mean(output$t)-output$t0
#se: 
sd(output$t)

```
You can extract the standard errors by using summary:

```
se <- summary(output)$bootSE

```