Exercise

# Is a BIBD even possible?

We saw in the video that it's possible a BIBD doesn't exist at all. It's useful to calculate the `lambda`

beforehand, and if the result isn't an integer, there isn't a possible BIBD.

Don't bust out the pen and paper yet: the `lambda()`

function has been defined for you. It takes as input `t`

= number of treatments, `k`

= number of treatments per block, and `r`

= number of repetitions. It then calculates `lambda`

according to this formula:
`r(k - 1) / (t - 1)`

.

Try the different combinations of `t`

, `k`

, and `r`

using `lambda()`

in your console, and choose the answer which does NOT have a BIBD.

Instructions

### Possible answers

`t`

= 2, `k`

= 2, `r`

= 2`t`

= 2, `k`

= 3, `r`

= 4`t`

= 3, `k`

= 4, `r`

= 11`t`

= 12, `k`

= 2, `r`

= 22