Clinical Chemistry Lab Exam I

MLS 4420

Population

an entire group of persons or objects

Sample

a portion of the population

Parameter

a property of the population

Statistics

numbers which attempt to capture all of the essential information about the whole data set

Independent variable

the quantity directly controlled by the experimenter; x-axis; left column in a table

Dependent variable

the quantity that changes due to the independent variable; y-axis; right column in a table; the result

Discrete data

a count of whole events, objects, or persons (e.g. the number of people with a diabetes)

Continuous data

the measure of a quantity, such as length, volume, or time, which can occur at any value (e.g. the blood glucose in the blood of a person with diabetes)

Relative frequency

the proportion of a sample that belongs to a particular parameter, better for large samples

Absolute frequency

the number of times a sample belongs to a particular parameter

Coefficient of variation

the quantity of standard deviation divided by the mean multiplied by 100, used to identify variability

1_2s

Westgard rule where one point is outside 2 standard deviations

1_3s

Westgard rule where one point is outside 3 standard deviations

2_2s

Westgard rule where two consecutive points (either within the same or across runs) fall outside of 2 standard deviations

R_4s

Westgard rule where the highest and lowest results span over 4 standard deviations

4_1s

Westgard rule where four consecutive points exceed 1+ or 1- limit

8_x

Westgard rule where eight consecutive points within one control OR across both controls, four consecutive controls each fall on the same side of the mean

68%

percent that falls within 1 SD

95%

percent that falls within 2 SD

98%

percent that falls within 3 SD

Trend

6-7 points that continue in the same direction across the mean

Shift

6-7 points that jump across the mean

√(sum of (difference from mean squared)/(number of assays-1))

formula for standard deviation