1$Most\ Probable\ Value\ $
$ (mpv)$
$\bar{x}=\ \frac{\sum x}{n}$

2$Residual\ or\ Deviation\ $
$ \left(v\right)$
$\ v=x-\bar{x}$
3Standard Deviation of
any Single Measurment
$\left(x\sigma n-1\right)\ =S_x=\ \pm\ \sqrt{\frac{{\sum\left(x-\bar{x}\right)}^2}{n-1}}$

4$Standard\ Error\ $
$of\ the\ Mean\ $
$ \left(S_{\bar{x}}\right)\ $
$S_{\bar{x}}=\ \pm\ \frac{S_x\ }{\sqrt n}$

5$Probable\ Error\ of\ the\ Mean\ $
$\left({PE}_m\right)$
${PE}_m=\pm0.6745\ S_{\bar{x}}$
6Probable Error of
Single Measurement
$\left({PE}_s\right)$
${PE}_s=\pm0.6745\ S_x$
7$Relative\ Precision\ \left(RP\right)$
or
$Relative\ Error\ \left(RE\right)$
$RP\ or\ RE=\ \frac{PE}{mpv}$
$RP\ or\ RE=\ \frac{PE}{PV}$
8$Single\ Error-\ Weighted\ Observation$
$\ (probable\ error\ given)\ \ $
$W=\ \frac{1}{{PE}^2}$

9$Single\ Error-\ Weighted\ Observation$
$(distances\ given)$
$W=\ \frac{1}{Distances}$

10$Single\ Error-\ Weighted\ Observation$
$(trials\ given)\ $
$W_E=\ \frac{1}{ \# \ of\ trials}$

11$Combination\ Error\ $
$(General\ Formula)$
$E_z=\ \pm\ \sqrt{\left(\frac{\delta(f)}{\delta a}\ E_a\right)^2+\left(\frac{\delta(f)}{\delta b}\ E_b\right)^2+\ldots}$

12$Error\ in\ Sum$
$sum=a+b+c$
$E_{sum}=\ \pm\sqrt{{E_a}^2+{E_b}^2+{E_c}^2}$
13$Error\ in\ Series$
$series=a+a+a$
$E_{series}=\ \pm\sqrt{{E_a}^2+{E_a}^2+{E_a}^2}$
14$Error\ in\ Product$
$product=ab$
$E_{product}=\ \pm\sqrt{\left({b\ E}_a\right)^2+\left({a\ E}_b\right)^2}$
15Horizontal Distance
$Tachymetry\ or\ Stadia\ Method$
$(Horizontal\ Sight)$
$H.\ D.\ =\ kS\ +\ C$

16Horizontal Distance
$Tachymetry\ or\ Stadia\ Method$
$(Inclined\ Sight)$
$H.\ D.\ =\ \left(kS\ cos\theta\ +\ C\right)\ cos\theta$

17Horizontal Distance
$Subtense\ Bar\ Method$
$H.D.\ =\ \frac{1\ m}{tan\ \left(\frac{\theta}{2}\right)}$

181 PACE
Toe to Toe Distance of Different Foot
Heel to Heel Distance of Different Foot
191 STRIDE
Toe to Toe Distance of SAME Foot
Heel to Heel Distance of SAME Foot
20$Pace\ Factor$
$Pace\ Factor\ =\ \frac{distance\ \ travelled}{ave.\ no.\ \ of\ \ paces}$
21$Measurement\ of\ $
$Horizontal\ Distances\ $
$True\ Dist.\ =\ Meas.\ Dist.\ \pm\ Corr.\ $
22$Correction\ in\ Taping$
$(C_L)$
$\frac{{c\ }_L^{single\ err.}\ }{Tape\ Length}\ =\ \frac{{C\ }_L^{total\ err.}}{Meas.\ Dist.}$
23$Correction\ in\ Temperature$
${(C}_t)$
$C_t=\ \alpha\ L_{\dfrac{tape}{recd}}\ \left(T_{obs}-T_{stnd}\right)$

24$Correction\ due\ to\ Pull$
$(C_p)$
$C_p\ =\ \frac{\left(P_{obs}-\ P_{stnd}\right)\ L}{A\ E}$

25$Correction\ due\ to\ Sag$
${(C}_s)$
$C_s\ =\ \frac{w^2\ L^3}{24\ \left(P_{obs}\right)^2}$

26$Correction\ due\ to\ Slope$
$(C_h)$
$Gentle\ slope\ \left(<20\% \right)\ $
$C_h=\ \frac{h^2}{2L_{incl}}$

27$Correction\ due\ to\ Slope$
$(C_h)$
$Steep\ slope\ \left(20\%\ -\ 30\% \right)\ $
$C_h=\ \frac{h^2}{2\ L_{\ incl}}\ +\frac{h^2}{8\ \left(L_{incl}\right)^3}$

28$Correction\ due\ to\ Slope$
$(C_h)$
$Very\ Steep\ slope\ \left(>30\%\right)$
$C_h=\ L_{incl}\ \left(1-\ cos\ \theta\right)$

29$Correction\ due\ to\ Sea\ Level$
$(C_{sea})$
$\frac{{L\ '}_{equi.\ \ sea}}{{R\ \ \ }_{earth}^{6400\ km}}\ =\ \frac{L_{\ recd}}{R_{\ earth}+h}$
30Vertical Distance
$Differential\ Leveling$
$elev\ {\rm BM}_B=\ elev\ {\rm BM}_A\ +\ \sum BS-\ \sum FS$

31Vertical Distance
$Double\ Rodded\ Leveling$
$elev\ {\rm BM}_B=\ \frac{elev\ {\rm BM}_{B1}\ +\ elev\ {\rm BM}_{B2}\ }{2}$
$elev\ {\rm BM}_{B1}=\ elev\ {\rm BM}_A\ +\ \sum{\rm BS}_1-\ \sum{\rm FS}_1$
$elev\ {\rm BM}_{B2}=\ elev\ {\rm BM}_A\ +\ \sum{\rm BS}_2-\ \sum{\rm FS}_2

32Vertical Distance
$Three\ Wire\ Leveling$
$elev\ {\rm BM}_{B}=\ elev\ {\rm BM}_A\ +\ \sum{\rm BS}-\ \sum{\rm FS}$

33Vertical Distance
$Reciprocal\ Leveling$
$h=\ \frac{h_1\ +\ h_2\ }{2}$

34Vertical Distance
$Profile\ Leveling$
$elev\ {\rm STA_B}=\ elev\ {\rm STA_A} +{ BS}-{IFS}$

35Leveling Adjustment
CONCEPT
$Two-Peg\ Test$
There was a deviation of horizontal sight due to poor calibration

36Leveling Adjustment
1st SET-UP
$Two-Peg\ Test$
$e_{b1}\ =\ e_{a2}$

37Leveling Adjustment
2nd SET-UP
$Two-Peg\ Test$
$e_{a1}\ =\ e_{b1}\ \ \ \nparallel \nparallel \ \ \ \frac{e_{a2}}{L_1}\ =\ \frac{e_{b2}}{L+\ L_1}$

38Leveling Adjustment
Concept
$Sensitivity\ of\ Level\ Tube$
39Leveling Adjustment
Level [not inclined] Vial (Level Tube)
$Sensitivity\ of\ Level\ Tube$
40Leveling Adjustment
Inclined (Level Tube)
$Sensitivity\ of\ Level\ Tube$