Test 2

Question 1

What is Normal Curve?

Answer 1

a bell shaped probability of distribution mean, median, mode are the same

Question 2

n-1 is?

Answer 2

Degrees of Freedom

Question 3

What is Median

Answer 3

the middle value of a body of data

Question 4

what is a T-Test?

Answer 4

Mathematical way to determine if there is a significant difference in the results obtained by two different methods for the same constituents

Question 5

What is Mean?

Answer 5

arithmetic average sum of individual variables divided by the number of variables in a sample

Question 6

What is Precision?

Answer 6

is a measure of how well a measurement device can reproduce the same measurement when repeatedly measuring one time

Question 7

What is Standard Deviation?

Answer 7

estimate of the degree of uniformity of the data, dispersion of variables around the mean

Question 8

What is Variance?

Answer 8

sum of the squares of the deviations of the variables from the mean. divided by the total number of variables less that one
S2 = ∑(X-M)2
________
n - 1

Question 9

What is Correlation Study

Answer 9

analysis samples are tested with two different methods and results are plotted on linear graph paper

Question 10

What is Mode

Answer 10

most frequently occurring variable in distribution

Question 11

What is Accuracy

Answer 11

a measurement of how close a true value is time and time again

Question 12

What is Coefficient Data

Answer 12

used to compare compatibility

Question 13

what is Range

Answer 13

difference between the highest and lowest distribution

Question 14

Quality Control gives you info on ______ of procedure/ laboratory analyzers?

Answer 14

accurate and precise reliability

Question 15

What is Shift?

Answer 15

four or more consecutive plots on, above or below the mean

-wrong setting, instrument, standard

Question 16

What is Trend?

Answer 16

indicated by four to six successive points in the same direction, increasing or decreasing

Question 17

Do laboratories establish their own normal ranges?

Answer 17

Usually depends on the lab, but the reference ranges must be varrified

Question 18

How do they go about establishing own normal ranges (how many data points needed, what kinds of patients do they use or not use, etc.)?

Answer 18

apparently healthy pt, or samples from the pop. that should be normal

Question 19

What is the purpose of a laboratory establishing its own normal range?

Answer 19

to establish normal range for the area population

Question 20

Would a single data point that fell out of control be used to determine the statistics for the next month’s QC chart? Explain

Answer 20

Yes, because it is considered random error

Question 21

Generally speaking, random error is due to what?

Answer 21

Human Error (chance)

Question 22

What is the Levey-Jennings Chart?

Answer 22

a chart used to plot QC values and to determine standard deviation 95% confidence limits best method to detect Shift and Trend.

Question 23

What info does the Levey-Jennings Chart Provide?

Answer 23

provides info about how well the analyzers are performing over time

Question 24

Define and precision?

Answer 24

Consistency

Question 25

Give the total % of a normal population that would be included in ±3SD from the mean

Answer 25

99.7%

Question 26

The standard deviation divided by the mean and multiplied by 100 gives you the

Answer 26

Coefficient Variation

Question 27

What are some steps you would take if you were running controls and they fell between ±2SD and ±3SD? What would you NOT do in this situation?

Answer 27

Do not run pt samples if it does not come in

Question 28

What percentage of the normal population will fall between the ±2SD and the ±3SD range on a normal curve?

Answer 28

4.2% between 2-3SD range