<span>p1=44/88=.50; p2=57/85=.67.
Under the null hypothesis of no difference, we pool the data to estimate the
common p of (44+57)/(88+85)=.584.
The test statistic is (.67-.50)/sqrt[(.584)(1-.584)(1/88 + 1/85)]=2.268 (which is stat sig. at a .095 level).</span>
Notice that if you go forward, the common ratio is 5. Each new term is found by mult. the previous term by 5.
If, on the other hand, you go backwards (terms decreasing), then you divide a term to find what the previous term was.
Here, divide 1 by 5 to find the first term. It's 1/5.
7/12 times 4 is 2 1/3. So 2 1/3 inches each week