AC Chp 2 Errors & Analysis

What is accuracy?

• A measure of how close a measure of central tendency is to the true value

• A measure of how far a measure of central tendency is to the true value

• A measure of how close a measure of central tendency is to the measured value

There are two kinds of experimental error. There are ____

• Random and determinate

• Random and systematic

• Experimental and non-experimental

• Systematic and indeterminate

Is this the correct formula for finding absolute error?

• Yes

• No

Define precision.

• A measure of spread of data about a central value that may be expressed as standard deviation

• A measure of how close a value is to an expected value

• A function of slope of calibration curve

Precision can be tested using replicate analysis by calculating its standard deviation. The higher the standard deviation, the greater the precision. Is this statement correct?

• Yes

• No

What does this picture indicate?

• Accurate and precise

• Accurate but not precise

• Precise but not accurate

• Not precise and not accurate

Why is accuracy and precision important?

• To obtain very pretty data

• To gather reliable and valid data

• Just 'cause

• To measure how good I am as a chemist

"The steeper the slope of a calibration curve, the more sensitive the data is" Would you say this statement is correct?

• Yes

• Nah

• Maybe

What quantity do you use to determine how accurate your experimental results are? There could be more than one answer

• Absolute error

• Percent relative error

• Standard deviation

• Variance

If you look at a ruler with your eyes NOT perpendicular to the line or mark on the ruler, what type of error would that be called?

• Parallax error

• Sampling error

• Measurement error

• Method error