Solved: Poly(3-hydroxybutyrate) (PHB), a semicrystalline

Chapter 1, Problem 44E

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QUESTION:

Poly(3-hydroxybutyrate) (PHB), a semicrystalline polymer that is fully biodegradable and biocompatible, is obtained from renewable resources. From a sustainability perspective, PHB offers many attractive properties though it is more expensive to produce than standard plastics. The accompanying data on melting point (°C) for each of 12 specimens of the polymer using a differential scanning calorimeter appeared in the article "The Melting Behaviour of Poly(3-Hydroxybutyrate) by DSC. Reproducibility Study" (Polymer Testing, 2013: 215-220).

             180.5      181.7      180.9      181.6      182.6      181.6

             181.3      182.1      182.1      180.3      181.7      180.5

Compute the following:

a. The sample range

b. The sample variance S2 from the definition (Hint: First subtract 180 from each observation.)

c. The sample standard deviation

d. S2 using the shortcut method

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QUESTION:

Poly(3-hydroxybutyrate) (PHB), a semicrystalline polymer that is fully biodegradable and biocompatible, is obtained from renewable resources. From a sustainability perspective, PHB offers many attractive properties though it is more expensive to produce than standard plastics. The accompanying data on melting point (°C) for each of 12 specimens of the polymer using a differential scanning calorimeter appeared in the article "The Melting Behaviour of Poly(3-Hydroxybutyrate) by DSC. Reproducibility Study" (Polymer Testing, 2013: 215-220).

             180.5      181.7      180.9      181.6      182.6      181.6

             181.3      182.1      182.1      180.3      181.7      180.5

Compute the following:

a. The sample range

b. The sample variance S2 from the definition (Hint: First subtract 180 from each observation.)

c. The sample standard deviation

d. S2 using the shortcut method

ANSWER:

Step 1 of 4

The computation is done using the following table

Sl. No

     x

( -

 

1

180.5

0.71487025

32580.25

2

181.7

0.12567025

33014.89

3

180.9

0.19847025

32724.81

4

181.6

0.06477025

32978.56

5

182.6

1.57377025

33342.76

6

181.6

0.06477025

32978.56

7

181.3

0.00207025

32869.69

8

182.1

0.56927025

33160.41

9

180.3

1.09307025

32508.09

10

181.7

0.12567025

33014.89

11

180.5

0.71487025

32580.25

Sum

1994.8

5.24727275

361753.2

Average

181.3455

We need to compute the following

a. The sample range is the difference between highest value and the lowest value.

        That is, Range = 182.6 - 180.3

                    Range = 2.3°C

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