3. You work in an analytical testing lab and have been asked by your supervisor to purchase new pH meters to replace your old supply. You have identified four potential suppliers and now need to evaluate the performance of each pH meter. You obtained a solution with a known pH of 5.5. You performed 10 replicate measurements of the pH of that known solution using each of the four different pH meters and obtained the data shown below. From the following data a. Calculate for the mean, standard deviation, and percent error for the data set A, B and C. b. Apply Q-test and Grubb's Test to determine if the extreme values are outliers. c. State the null and alternative hypotheses. d. Use MS Excel or Google sheets to determine if there is statistically significant difference between the three methods at 95% confident level.

An ore sample was analyzed for its Fe content. Student A analyzed the sample a total of six times and her results had a standard deviation of 1.33. The same sample was analyzed five times by Student B and his results had a standard deviation of 3.42. To determine if their standard deviations are similar, they perform an F test. The calculated F value is and the table value of Fis 3 in your book for critical values of F. O 6.61; 7.39 O 6.61; 9.36 O 0.151; 9.36 O 2.57; 7.39 O 6.61; 6.98 Refer to Table 4-

Often the analyst will compare known quantities of analyte to unknown quantities of the material to be analyzed. This may be done in one of three ways: -use calibration curves; use standard additions; or use internal standards. The method of standard additions would be used when A) the quantity of sample analyzed or the instrument response varies from run to run.   B) the standard solutions and the unknown solution all have similar characteristics are unaffected by the other material in the sample.   C) the sample composition is unknown or complex and affects the analytical signal.

Plot a professional quality standard curve (absorbance vs. protein amount in µg) with an appropriate title and caption underneath the plot from the data give above. The caption should include the best-fit data.

Trial 1 Trial 2 Trial 3 Initial burette reading (mL) 2.29   1.41   1.95   Molarity of NaOH (M) 0.100   0.100   0.100   Volume of vinegar sample (mL) 5.00   5.00   5.00   Final burette reading (mL) 50.37   49.39   49.84 Table 2. Titration data   Trial 1 Trial 2 Trial 3 Initial burette reading (mL) 2.29   1.41   1.95   Molarity of NaOH (M) 0.100   0.100   0.100   Volume of vinegar sample (mL) 5.00   5.00   5.00   Final burette reading (mL) 50.37   49.39   49.84   Expected color at end point       Volume of NaOH used (mL) 48.08   47.98   47.89  Compute for the ff: a.   Average moles of acetic acid (mol)? b.  Average molarity of acetic acid (M)? c.  Average molarity of acetic acid (M)?

Calculate the sample standard deviation, s, for this set of data: 1.9, 1.5, 6.0, 2.0, 1.4, 1.2 Report your answer to the fourth decimal place.