If the uncertainty in f really is ±0.05 Hz that is an error of less than 1% (0.05 in 17.5 is 0.28%)
If the uncertainty in wavelength really is ±0.01m then that is about 3% max (0.01 in 0.345)
This gives a maximum uncertainty in v of between 3 and 4%.
Your results give an uncertainty (using the spread of values) of about 0.5 in 18
That is a little under 3%
So there seems to be consistency.
By far the larger source of possible error in this experiment is the measurement of the wavelength. (See also below*)
However, it looks a bit suspicious as the value of v seems to be increasing as you increase the number of antinodes.
Can you be certain that this apparent increase is just due to random experimental error, or due to something else? Would not the values of v lie randomly about the mean value, rather than seeming to show a (slightly) increasing trend?
Other comments:
There's something that puzzles me about these results.
You say they are the first 5 standing wave patterns.
In this case, shouldn't the first one be the fundamental (lowest) frequency?
The others are then all a multiple (2f, 3f, 4f, 5f etc) times this?
In your results this doesn't happen. The others are not a whole multiple of the 1st. (17.5, 26.2, 35.2, 44.3, 53.8)
It looks like the fundamental is around 9Hz and these are all multiples of that. Did you measure the case with one loop, a single antinode in the centre of the wave? This would have been the 1st (fundamental) frequency.
By the way, this would not affect your results or calculation, but would need to be commented on.
* There could be a small systematic error in the results. This is due to the fact that the end of the string where the resonator is, is not quite a node. After all, a node is a place of zero displacement, and the resonator is moving there, so how can it be a true node? In reality, so long as the amplitude of the resonator is small it doesn't cause a problem. Even so, it means that the measurement of the wavelength is always out by a small amount for each vibration mode. As the wavelengths get smaller, this small difference gets proportionally larger. This could account for the fact that your velocity values seem to increase as you increase the frequency.
Of course, there could be other reasons.
Most text book conveniently ignore this!