And that is why we study statistics (right @Dr_Feelgoood212 ?). The variation between individual samples of each group may be larger than the average difference between the two groups. Which means that although on average, there is a difference, there is a greater difference between individual samples.
From a practical point of view then (since you are buying one sample not the average) you must measure (play) one to know if it is the right one.
What colour matchbooks?
Short answer, yes.
Long answer,
Pretty much. But for a quantitative study, the sample would need to be at least 10 basses of each wood, with minimal variation as possible, like
@JIO said about neck-thru vs bolt on, still applies, must be same shape, same hardware (not same model, but actually transfer the hardware, strings, pups, electronics over to each bass), same batch of wood (for each type of wood), etc. Then to rule out the individuality of the difference in the batch of wood, you'd have to test another batch of each wood.
Most importantly, you'd need to take quantitative measurements, more so that tone is highly subjective. Meaning you'd need to put each bass on some form of measuring device like an oscilloscope.
But doing all this is overkill and not very feasible, plus tone is subjective, this is why people they try out every bass/guitar in multiple stores, and then pick a specific bass/guitar at a specific store, they found the one that is just right.
EDIT: I missed the part where you said basically the same thing.
Colour of matchbook must match the colour of the bass, I thought that was common knowledge