Excel STDEV

Famoxadone, IN-JS940, and IN-KZ007 residues are measured in soil (p-g kg ), sediment (p-gkg ), and water (pgL ). Quantification is based on analyte response in calibration standards and sample extract analyses determined as pg mL Calibration standard runs are analyzed before and after every 1 samples in each analytical set. Analyte quantification is based on (1) linear regression analysis of (y-axis) analyte concentration (lagmL Q and (x-axis) analyte peak area response or (2) the average response factor determined from the appropriate calibration standards. The SLOPE and INTERCEPT functions of Microsoft Excel are used to determine slope and intercept. The AVERAGE and STDEV functions of Microsoft Excel are used to determine average response factors and standard deviations. 

The sample mean and sample standard deviation are obtained by using Microsoft Excel with the commands AVERAGE(B2 B7) and STDEV(B2 B7) when the observations are in cells B2 to B7. 

In Microsoft Excel, these are calculated by the functions =AVERAGE (range and =STDEV (range, respectively, where range is the range of cells containing the n data (e.g., Al A5). It is said that x is an estimate of p, and s is an estimate of a. 

In this exercise, we have learned to calculate a mean, using both the built-in Excel AVERAGE function and a formula of our own design. In Chapter 6, we will use STDEV and other functions to complete our analysis of the data from the gravimetric determination of chloride that we began in Chapter 2. You may now close Excel by typing File/Exit or proceed to Chapter 6 to continue with the spreadsheet exercises. 

To calculate the 95% confidence limits using Excel, simply type into a blank cell =STDEV(range) TINV(0.05, n-1)/SQRT(n), where range is the range of cells containing the n data. Typing =TINV(0.05, n—1) gives the f-value alone. 

To solve this example you first need the mean and standard deviation. Use the Excel commands =AVE RAGE (range) and =STDEV(ranpe) which give 7.14 and 3.96 for the mean and standard deviation, respectively. 

Excel has built-in functions for average and standard deviation. Enter the numbers 7, 18, 10, and 15 in cells A1 through A4 of a spreadsheet. In cell A5, enter the formula =AVER AGE( A1 A4) and in cel 1A6, enter the formula =STDEV( A1 A4) . Results in the spreadsheet in the margin reproduce those in the example above. For a list of built-in functions, go to the Formulas ribbon and select Insert Function. In the window that appears, you can browse categories of functions or all functions. 

Check your results by using the Excel fnnctions AVERAGE, STDEV, MAX, and MIN. 

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