lab 1 post lab - Exercise 1: How do scientists collect and...

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Unformatted text preview: Exercise 1: How do scientists collect and analyze data? Post Lab Question 1 Weight of Water Measured by Various Volumetric Measuring Devices Trial 1 2 3 4 5 100 mL beaker (g) 55.018 g 54.069 g 55.482 g 55.585 g 54.211 g 100 mL graduated cylinder (g) 58.374 g 59.136 g 59.104 g 59.040 g 59.268 g 6 7 8 55.770 g 55.736 g 56.802 g 59.191 g 59.190 g 59.438 g Mean example calculation Standard Deviation example calculation Question 2 (a) 2.706 g 2.665 g 2.640 g (55.018+54.069+55.482+55.585+54.211+55.770+55.736+56.802 √[ (55.018²+54.069²+55.482²+55.585²+54.211²+55.770²+55.736²+56. percent error of mean example calculation Mean standard deviation percent error of mean 10 mL graduated cylinder (g) 2.624 g 2.614 g 2.590 g 2.746 g 2.706 g ( |55.33413­60|÷ 60 ) * 100 = 7.78% 55.33413 g 0.890065 g 7.78% 59.09263g 0.31405g 1.51% 3.25638g 1.78652g 8.55% When measuring 60 mL of dH2O, which measuring device seems to be more accurate, th cylinder? Be sure to explain your answer. The 100 mL graduated cylinder was more accurate because the values obtained were clos the 100mL beaker. (b) When measuring 60 mL of dH2O, which measuring device seems to be more precise, the cylinder? Be sure to explain your answer. The 100 mL graduated cylinder was more precise than the beaker for measuring 60 mL of contained smaller line increments that made getting the actual value easier. ( c ) Question 3 (a) Use the Student’s t­test to test the null hypothesis that there is no difference in the accurac graduated cylinder when measuring 60 mL of dH2O. Be sure to show your p value and ex When measuring 3 mL of dH2O, which measuring device seems to be more accurate, the pipet? The 5 mL pipet was more accurate because the values obtained were closer to the actual (b) When measuring 3 mL of dH2O, which measuring device seems to be more precise the 10 The 5 mL pipet was more precise than the graduated cylinder for measuring 3 mL of water line increments that made getting the actual value easier. ( c ) Question 4 (a) Use the Student’s t­test to test the null hypothesis that there is no difference in the accurac the 5 mL pipet when measuring 3 mL of dH2O. Be sure to show your p value and explain When measuring 0.17 mL of dH2O, which measuring device seems to be more accurate, 1,000 μL micropipettor? The 100 – 1,000 μL micropipettor was more accurate because the values obtained were c (b) ( c ) Question 5 When measuring 0.17 mL of dH2O, which measuring device seems to be more precise, th 1,000 μL micropipettor? The 100 – 1,000 μL micropipettor was more precise than the 20 – 200 μL micropipettor fo 100 – 1,000 μL micropipettor contained smaller line increments that made getting the actu Use the Student’s t­test to test the null hypothesis that there is no difference in the accurac 20 – 200 μL micropipettor and the 100 – 1,000 μL micropipettor when measuring 0.17 mL and explain your conclusions. ollect and analyze data? b Volumetric Measuring Devices 5 mL pipet (g) 2.969 g 2.877 g 2.949 g 3.013 g 2.954 g 20­200 µL pipettor (g) 0.166 g 0.166 g 0.166 g 0.163 g 0.164 g 100­1000 µL pipettor (g) 0.1765 g 0.1750 g 0.1720 g 0.1785 g 0.1705 g 2.990 g 2.969 g 2.901 g 0.162 g 0.170 g 0.169 g 0.1755 g 0.1785 g 0.1820 g +54.211+55.770+55.736+56.802) ÷ 8 = 55.33413g ²+54.211²+55.770²+55.736²+56.802²) ÷ 7 ]= 0.590065g 13­60|÷ 60 ) * 100 = 7.78% 2.95275g 0.04469g 1.58% 0.16575g 0.00276g 2.50% 0.17606g 0.00371g 3.56% e seems to be more accurate, the 100 mLbeaker or the 100 mL graduated use the values obtained were closer to the actual value of 60 grams than e seems to be more precise, the 100 mL beaker or the 100 mL graduated e beaker for measuring 60 mL of water because the graduated cylinder actual value easier. BC Ttest #VALUE! ere is no difference in the accuracy of the 100 mL beaker and the 100 mL sure to show your p value and explain your conclusions. seems to be more accurate, the 10 mL graduated cylinder of the 5 mL obtained were closer to the actual value of 3mL. seems to be more precise the 10 mL graduated cylinder of the 5 mL pipet? inder for measuring 3 mL of water because the 5 mL pipet contained smaller . ere is no difference in the accuracy of the 10 mL graduated cylinder and to show your p value and explain your conclusions. vice seems to be more accurate, the 20 – 200 μL micropipettor or the 100 – cause the values obtained were closer to the actual value of 17 mL. vice seems to be more precise, the 20 – 200 μL micropipettor or the 100 – n the 20 – 200 μL micropipettor for measuring 17 mL of water because the ments that made getting the actual value easier. ere is no difference in the accuracy of the ipettor when measuring 0.17 mL of dH2O. Be sure to show your p value ...
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This note was uploaded on 09/04/2011 for the course BIOL 1406 taught by Professor Bostic during the Summer '09 term at Austin Community College.

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