1. Explain the difference between accuracy and precision 2. Name a statistical quantity that can be used to indicate an accuracy level. 3. Name a statistical quantity that can be used to indicate a precision level. 4. To what level of accuracy (1 cm, 0.1 cm, 0.01 cm. 0.001 cm) can the ruler used to measure the lengths of the pencil in the above example be read?

Accuracy explains the closeness or nearness of a measured or studied quantity to the actual value while precision explains the ability of a measuring device to get the same measured value when measured repeatedly

2 Accuracy is determined by percentage error while precision is by taking the ratio of standard deviation with the individual measurements

3. The accuracy of the ruler is 0.001 cm because that's the least measurement it can take

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia