Exam 1: Mathematics and Statistics

Readers are encouraged to use Microsoft Excel to solve this problem.What is the coefficient of variation (CV) of the following five numbers: 6.40, 7.20, 3.50, 9.20, 5.10?

Readers are encouraged to use Microsoft Excel to solve this problem.What is the mean of the following five numbers: 6.40, 7.20, 3.50, 9.20, 5.10?

Using the regression equation in Problem 31, if your training program exam score was 84, what does the regression equation predict for your board score?

A new gamma camera/computer system that uses a new method of calculating cardiac ejection fraction (EF) is installed in a nuclear medicine department.The department decides to calculate EF for the next 25 patients on both the old gamma camera and the new gamma camera before discontinuing the use of the old camera.In the future, if it is desirable to convert the new EF value to that which would have been obtained on the old gamma camera (e.g., to assess if the patient's EF had changed), the mathematical analysis to be used is called a(n)

A source of ${ }^{131} \mathrm{I}\left[\mathrm{t} \frac{1}{2}=8.05 \mathrm{~d}\right]$ is delivered to the nuclear medicine department calibrated for 100 mCi at 8:00 AM on Monday.If this radioactivity is injected into a patient at noon on Tuesday, what radioactivity will the patient receive?

A ⁹⁹Mo-^99mTc generator is eluted Monday at 7:00 AM, producing 1.8 Ci of ^99mTc in the eluate vial, in 20 ml saline.What volume of eluate should be withdrawn from the eluate vial into a syringe in order to inject a patient with 20 mCi of ^99mTc at 3:00 PM? (Given the half-life of ^99mTc is 6.02 hours.)

A long-lived radioactive source is counted for 1 minute and yields 10,000 counts.If this source is counted immediately again, there is a 95% probability that the result will be in the range:

The radiation intensity from a point source of ^99mTc is 9 mR/hr at 3 m from the source.If the distance is changed to 9 m, what is the new radiation intensity?

A ⁹⁹Mo-^99mTc generator is calibrated for 1.00 Ci of ⁹⁹Mo at 7:00 AM Monday.The generator is eluted daily Monday through Friday at 8:00 AM, but the workload is especially heavy on Friday so the generator is eluted again at 3:00 PM to obtain more ^99mTc.Assuming 100% elution efficiency, how many mCi of ^99mTc will be eluted at 3:00 PM Friday?

Using Table 1-9 in the book, does a linear correlation coefficient r = 0.95 for n = 5 data points indicate a statistically significant linear relationship between the x and y variables?

Readers are encouraged to use Microsoft Excel to solve this problem.In a nuclear medicine technology training program, the students wonder if their final exam grade in their training program is related to their subsequent board score on the NMTCB exam.The five students attain the following pairs of scores (exam score, board score) = (72, 60), (84, 74), (88, 71), (68, 60), (91, 79).What is the linear correlation coefficient, r, between exam score and board score?

Which expression describes the operation of the gamma camera in question 16?

What is the standard deviation of 40,000 counts?

What is the proper number of significant figures for the quotient (6.1 *10^-2)/(0.1232)?

A radioactive source decays from 20 mCi to 2.5 mCi in 18 hours.What is the physical half-life?

A technologist is sitting near a bone mineral densitometer, which is a point source of x-rays.If the x-ray intensity at 1 m from the x-ray beam is 0.20 mR/hr, to what distance from the x-ray beam should the technologist move to decrease total weekly exposure to the occupational limit of 2 mR for a 40-hour workweek?

A patient's thyroid is counted with the thyroid probe and produces 8000 counts.Then the patient is removed and background is found to be 2000 counts.The (net counts) ± (standard deviation in the net counts) in this patient is

The gamma camera seems to be producing erratic results.A ⁵⁷Co flood source is counted 10 times, producing the following count values: 1000, 975, 1032, 1096, 982, 997, 1012, 1090, 994, 977.What is the chi-square value for these counts?

The biological half-life of ¹³¹I in a particular patient is 30 days.The physical half-life is 193 hours.If the patient's thyroid is counted with the thyroid probe detector, what effective half-life will be observed?

A source of ¹⁸F (t_1/2 = approximately 2 hr) is noted to contain 3 mCi at noon.What was the radioactivity at 8:00 AM that same day?