7. The following calibration graph data were obtained for determination of p-fluorophenol by LC/ESI/MS.
Estimate the linearity of the data using the lack-of-fit test (at confidence interval 95%). First, find the number of degrees of freedom, Fcalc and Ftab (with two decimal places) using the lack-of-fit test. Finally, make the decision whether the data is linear or not based on the results of the lack-of-fit test (taking into account the intercept).
The following calibration graph data were obtained for determination of p-fluorophenol by LC/ESI/MS.
C (ppb) |
Signal 1 |
Signal 2 |
Signal 3 |
Signal 4 |
Signal 5 |
Signal 6 |
Signal 7 |
Signal 8 |
Signal 9 |
Signal 10 |
20 |
36 449 861 |
36 888 155 |
32 219 333 |
33 196 471 |
32 326 262 |
35 074 226 |
28 129 835 |
36 848 161 |
39 674 913 |
33 808 145 |
30 |
40 351 801 |
41 797 570 |
40 528 223 |
45 076 575 |
47 327 788 |
41 996 321 |
44 686 369 |
49 518 885 |
51 429 781 |
45 594 101 |
40 |
66 063 890 |
55 178 465 |
67 927 212 |
62 250 446 |
65 294 621 |
63 856 017 |
58 586 452 |
61 876 327 |
64 588 452 |
72 767 976 |
50 |
75 849 041 |
66 870 341 |
68 518 238 |
82 923 976 |
70 050 481 |
67 712 405 |
62 964 889 |
79 380 677 |
82 290 539 |
72 643 550 |
60 |
91 162 054 |
93 907 067 |
97 300 810 |
80 248 759 |
89 904 739 |
85 377 851 |
96 722 100 |
87 694 620 |
72 274 178 |
79 284 838 |
70 |
97 109 471 |
91 566 813 |
96 975 278 |
92 257 334 |
92 740 327 |
94 266 014 |
92 254 969 |
99 750 169 |
96 505 415 |
97 801 240 |
80 |
107 230 631 |
106 149 105 |
108 177 108 |
104 742 812 |
101 610 922 |
102 576 475 |
102 545 700 |
109 925 570 |
109 492 124 |
105 605 149 |
90 |
109 824 920 |
108 295 836 |
110 294 873 |
109 376 258 |
107 283 751 |
110 924 823 |
109 347 856 |
109 925 570 |
110 927 435 |
107 165 040 |
100 |
110 000 871 |
110 935 700 |
100 984 517 |
109 376 258 |
107 283 751 |
110 924 823 |
109 347 856 |
109 925 570 |
108 952 742 |
101 844 380 |
For use with ValChrom: st_3.2_6_linearity_lof.xls
Please evaluate the linearity of the corresponding calibration graphs by using the lack-of-fit test and decide whether it is justified to use a linear calibration model.
Number of degrees of freedom of the numerator:
Number of degrees of freedom of the denominator:
Fcalc (two decimal places, please use dot as decimals separator):
Ftab (two decimal places, please use dot as decimals separator):
The data is: