# Statistics: Designs and Treatments

Topics: Randomness, Water, Design of experiments Pages: 4 (1034 words) Published: March 8, 2008
Boiling point of Salt Water Experiment

Ex.3: For experiment 2, Complete steps (a)-(c) of the checklist. Experiment 2: Does the boiling point of water differ with different concentrations of salt?

CheckList
(a)Define the objectives of the experiment
The purpose of this experiment is to determine the boiling point of water with different levels of concentration of salt.

(b)Identify all sources of variation
(i)Treatment factors and their levels
The treatment factor in this experiment is salt water of different concentrations. It can be chose to have three levels: low, medium, and high concentrations relative to the same amount of water. The levels are coded 1 for low, 2 for medium, and 3 for high.

(ii)Experimental units.
The experimental units will be the identical beakers and heaters that will be assigned to each level of salt water. The salt from the same package will be divided into three amounts represent three different levels  low, regular, and high, and the weight of each amount will be weighted on a digital laboratory scale and should be corresponding to the required assigned amount for each level. The experiment should be done at the same place and the same time. Salt should be completely dissolved in water before heating, so salt water is also an experimental unit.

(iii)Blocking factors, noise factors, and covariates.
The blocking factors will be the types of salt, as each type of salt might be different in their composition, e.g. Producing area, treatments to the salt before packagingetc. Different composition of salt will have different solubility and thus result in a different boiling point. Apart from these differences in the composition of the salts, the amount of salt might not be as precise as the required amount, due to measurement errors. This also applies on the measurement of the amount of water for each level of salt, as well as the temperature of water.

(c)Choose a rule by which to assign the experimental...