Deck 8: Statistics

Question 1

If an experiment produces a result having a p value less than 0.05,what is the probability that any differences found would have been observed even if the null hypothesis is true?

A) Less than 1 chance in 10
B) Less than 1 chance in 20
C) Less than 1 chance in 100
D) Less than 1 chance in 200

Answer 1

Less than 1 chance in 20

Question 2

The coefficient of determination is

A) the ratio of the explained variation to the total deviation.
B) the ratio of the explained variation to the total variation.
C) the ratio of the unexplained deviation to the explained deviation.
D) the ratio of the unexplained deviation to the total variation.

Answer 2

the ratio of the explained variation to the total variation.

Question 3

A colleague generates a best-fit line through a set of data points and asks you to confirm its usefulness and goodness-of-fit.You perform a root-mean-squared-error (RMSE)calculation and come up with a very small RMSE value.Based on this value you determine that the best-fit line

A) deviates far from the data points.
B) fits the data well.
C) is useless for interpolation but valid for extrapolation.
D) predicts a value that is too far from the actual value.

Answer 3

fits the data well.

Question 4

Using linear regression,you compare two different methods for quantifying LDL in a serum sample.Which of the following is NOT acceptable practice when using regression lines?

A) Calculation of the slope of the best fit line through the data points
B) Extrapolation of points outside the standard curve
C) Identification of the y-intercept using the slope of the standard curve
D) Interpolation of points within the range of the standard curve

Question 5

Why is it necessary for a clinical laboratory professional to develop a strong understanding of statistics?

A) To comprehend data published in research papers and prepare data for possible publication
B) To determine whether laboratory equipment is functioning properly
C) To understand manufacturer instructions for testing methods and laboratory equipment
D) All of the above

Question 6

Which of the following sets of data would be bimodal?

A) 2, 2, 5, 6, 9, 9, 10, 12, 15, 17, 19
B) 2, 4, 6, 8, 10, 12, 14, 16, 18
C) 3, 3, 3, 4, 5, 6, 7, 9, 11, 14, 14
D) 3, 3, 4, 5, 6, 7, 9, 11, 11, 14, 17

Question 7

A laboratory technician measures the concentration of serum glucose in a sample ten times and obtains the following results: 32,84,84,86,87,87,87,88,89,89
Which of the following is most impacted by the presence of the outlier value?

A) Mean
B) Median
C) Mode
D) Both A and B are correct.

Question 8

What does the mode of a data set represent?

A) The average of the value of all the data
B) The inverse of the mean calculated from all the values
C) The median value of the data set
D) The value that occurs most frequently

Question 9

The correlation coefficient of two variables is r = 0.5.What is the coefficient of determination for these variables?

A) -0.10
B) -0.25
C) 0.10
D) 0.25

Question 10

The central tendency of a numerical data set refers to

A) accuracy.
B) the pattern created by the data when plotted on a logarithmic scale.
C) the precision of the equipment from which the data were obtained.
D) the value that typifies the data.

Question 11

How does one calculate the mean of a data set?

A) Add all the values together and divide the sum by the number of values.
B) Add the largest and smallest value and divide the sum by 2.
C) Add the two largest values and divide the sum by the number of values.
D) Add the two middle values and divide the sum by 2.

Question 12

Which of the following statements regarding significance tests is true?

A) Nonrejection of the null hypothesis does not mean it is true.
B) Significance thresholds are fixed and logical.
C) Statistical significance is equal to practical significance.
D) The p value is fixed and obvious.

Question 13

The standard deviation of a data set can be calculated from the following equation. s =
$\sqrt{\frac{\sum_{i=1}^{n}\left(x_{i}-x\right)^{2}}{n-1}}$
What does the value under the sigma (i = 1)represent?

A) The value of the final data point
B) The value of the first data point
C) The value of the mean
D) The value of the mode

Question 14

When linear regression fails to fit a straight line to the data,what method can be applied to determine the relationship between two variables?

A) Coefficient determination
B) Expansion of the sum
C) Nonlinear regression
D) Specimen pairing

Question 15

What is a major disadvantage of just reporting the mean,median,and mode of a data set?

A) All these values are subjective and open to interpretation by the person making the calculations.
B) None of these values tell how widely dispersed the data are around it.
C) The information provided by the mean, median, and mode are not related to each other.
D) The values do not indicate why the data were collected.

Question 16

A manufacturer-supplied sample of serum glucose is known to contain 85 mg/dL.A co-worker runs a test of the sample on a new piece of laboratory equipment and determines it to be 84 mg/dL.What can be inferred about the new laboratory equipment?

A) It is accurate.
B) It has no standard deviation.
C) It is precise.
D) Both A and C are correct.

Question 17

You are provided the following set of data: 20,21,28,42,43,43,50
Which value represents the median of this data set?

A) 20
B) 36
C) 42
D) 43