BOC 8: Laboratory Operations - Lab Mathematics
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| 150909556 | 127. An automated CK assay gives a reading that is above the limits of linearity. A dilution of the serum sample is made by adding 1 mL of serum to 9 mL of water. The instrument now reads 350 U/L. The correct report on the undiluted serum should be: | 3,500 U/L | |
| 150909557 | 128. The unit of measure for a standard solution is: | mg/mL | |
| 150909558 | 129. A glucose determination was read on a spectrophotometer. The absorbance reading of the standard was 0.30. The absorbance reading of the unknown was 0.20. The value of the unknown is: | 2/3 the standard. | |
| 150909559 | 130. A tech is asked by the supervisor to prepare a standard solution from the stock standard. What is the glassware of choice for this solution? | Volumetric flask. | |
| 150909560 | 131. How many mL of red blood cells are to be used to make 25 mL of a 4% red cell suspension? | 1 mL | |
| 150909561 | 132. The volume of 25% stock of sulfosalicylic acid needed to prepare 100 mL of 5% working solution is: | 20 mL | |
| 150909562 | 134. How many grams of sodium chloride are needed to prepare 1 L of 0.9% normal saline? | 9.0 | |
| 150909563 | 138. Which of the following is the formula for standard deviation? | square root (of sum of squared differences)/(N-1) | |
| 150909564 | 139. The acceptable limit of error in the chemistry lab is 2 SD. If you run the normal control 100 times, how many of the values would be out of the control range due to random error? | 5 | |
| 150909565 | 140. A mean value of 100 and SD of 1.8 mg/dL were obtained from a set of glucose measurements on a control solution. The 95% confidence interval in mg/dL would be; | 94.6-105.4 | |
| 150909566 | 141. When 0.25 mL is diluted to 20 mL, the resulting dilution is: | 1:80 | |
| 150909567 | 142. When the exact concentration of the solute of a solution is known and is used to evaluate the concentration of an unknown solution, the known is: | Standard. | |
| 150909568 | 143. A serum glucose sample was too high to read, so a 1:5 dilution using saline (dilution A) was made. Dilution A was tested and was again too high to read. A further 1:2 dilution was made using saline (dilution B). To calculate the result, the dilution B value must be multiplied by: | 10 | |
| 150909569 | 144. In performing a spinal fluid protein determination, the specimen is diluted 1 part spinal fluid to 3 parts saline to obtain a result low enough to measure. To calculate the protein concentration, the result must be: | Multiplied by 4 | |
| 150909570 | 147. If 0.5 mL of a 1:300 dilution contains 1 antigenic unit, 2 antigenic units would be contained in 0.5 mL of a dilution of: | 1:150 | |
| 150909571 | 151. Which of the following if the formula for calculating the dilution of a solution? | V1 x C1 = V2 x C2 | |
| 150909572 | 152. A colorimetric method calls for the use of 0.1 mL of serum, 5 mL or reagent and 4.9 mL of water. What is the dilution of the serum in the final solution? | 1:100 | |
| 150909573 | 153. Four mL of water are added to 1 mL of serum. This represents which of the following serum dilutions? | 1:5 | |
| 150909574 | 154. Which of the following is the formula for calculating a percent (w/v) solution? | grams of solute/volume of solvent x 100 | |
| 150909575 | 155. A solution contains 20 g of solute dissolved in 0.5 L of water. What is the percentage of this solution? | 4% | |
| 150909576 | 156. how many grams of sulfosalicylic acid (MW = 254) are required to prepare 1 L of 3% (w/v) solution? | 30 | |
| 150909577 | 157. How many mL of a 3% solution can be made if 6 grams of solute are available? | 200mL | |
| 150909578 | 159. The following 5 sodium control values in unit (mEq/L) were obtained: 140, 135, 138, 140, 142 Calculate the coefficient of variation. | 1.9% | |
| 150909579 | 160. The statistical term for the average value is the: | Mean | |
| 150909580 | 161. The most frequent value in a collection of data is statistically known as the: | Mode | |
| 150909581 | 162. The middle value of a data set is statistically known as the: | Median | |
| 150909582 | 163. Which of the following is the formula for arithmetic mean? | Sum of values/number of values | |
| 150909583 | 164. Given the following values: 100, 120, 150, 140, 130 What is the mean? | 128 | |
| 150909584 | 165. Which of the following is the formula for coefficient variation? | (standard deviation x 100)/mean | |
| 150909585 | 167. The sodium content (in grams) in 100 grams of NaCl is approx: | 40 | |
| 150909586 | 171. Which of the following is the formula for calculating the gram equivalent weight of a chemical? | MW/oxidation number | |
| 150909587 | 172. 80 grams of NaOH (MW = 40) are how many moles? | 2 | |
| 150909588 | 173. A serum potassium (MW = 39) is 19.5 mg/100mL. This value is equal to how many mEq/L? | 5.0 | |
| 150909589 | 174. Which of the following is the formula for calculating the number of moles of a chemical? | g/GMW | |
| 150909590 | 175. A 1 molal solution is equivalent to: | A solution containing 1 mole of solute per kg of solvent. | |
| 150909591 | 176. Which of the following is the formula for calculating the molarity of a solution? | number of moles of solute/L of solution | |
| 150909592 | 181. how many mL of 0.25 N NaOH are needed to make 100 mL of a 0.05 N solution of NaOH? | 20 mL |