Practice problems below are three practice problems that will you in completing the activities at the introduc- tory lab. you are more than welcome to try them or even complete them before attending the lab session. there is no preparatory assignment for this laboratory. for the questions that require calculations, remember to express your final answers in the "best estimate – uncertainty" form and include full working and units. 1. find the sum of the following lengths: 102.3 + 0.2 cm, 44.8 +0.2 cm and 5.67 + 0.08 cm, assuming that the measurements are independent. (for general overview, see "sums and differences" in section 1.2; for further details, see appendix section a.4.1.) 3. several readings of the diameter of a sphere vield the following values: 24.75 mm, 24.82 mm, 24.87 mm, 24.79 mm, 24.75mm 24.95 mm, 24.71 mm, 24.81 mm, 24.65 mm, 24.69 mm. calculate the mean radius, the standard deviation of the radius measurements, the uncertainty in the mean radius and report the measured radius with the correct signif- icant figures. (for general overview, see - statistical analysis in large data sets" in section 2; for further details, see appendix sections a.3.1, a.3.3 and a.4. note: you do not need to show working for the standard deviation