Answer
Respectively: $0.5711 \frac{g \space O}{g \space N}; 1.142 \frac{g \space O}{g \space N}; 2.284 \frac{g \space O}{g \space N}; 2.885 \frac{g \space O}{g \space N}$
Work Step by Step
First compound:
$\frac{mass \space of \space oxygen (g)}{mass \space of nitrogen(g)} = \frac{17.60 \space g \space O}{30.82 \space g \space N} = 0.5711 \frac{g \space O}{g \space N}$
Second compound:
$\frac{mass \space of \space oxygen (g)}{mass \space of nitrogen(g)} = \frac{35.20 \space g \space O}{30.82 \space g \space N} = 1.142 \frac{g \space O}{g \space N}$
Third compound:
$\frac{mass \space of \space oxygen (g)}{mass \space of nitrogen(g)} = \frac{70.40 \space g \space O}{30.82 \space g \space N} = 2.284 \frac{g \space O}{g \space N}$
Fourth compound:
$\frac{mass \space of \space oxygen (g)}{mass \space of nitrogen(g)} = \frac{88.00 \space g \space O}{30.82 \space g \space N} = 2.885 \frac{g \space O}{g \space N}$