Statistical Report Writing Sample No.1.
Introduction. In the manufacture of soft contact lenses the strength of the lens should not
be too high. The data set contains the strength index (hardness and elasticity) of lenses produced using
materials from three different suppliers. The following table consists of two variables, Suppliers and
Strength. Suppliers are categorical values, 1, 2, or 3, indicating the different suppliers. Strength is
numerical values of strength index: The larger the value is, the higher the strength of the lens.
Suppliers
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
Strength
189.9
191.9
190.9
183.8
185.5
190.9
192.8
188.4
189.0
156.6
158.4
157.7
154.1
152.3
161.5
158.1
150.9
156.9
218.6
208.4
187.1
199.5
202.0
211.1
197.6
204.4
206.8
Data Analysis. The descriptive statistics of mean, median, standard deviation, and quartiles
are summarized for each supplier. Comparing the mean values, we found that Supplier No.2 has the
least strength among the three suppliers.
Suppliers
1
2
3
Mean
189.2333
156.2778
203.9444
S.D
L.Quartile Median U.Quartile
2.958885
188.4
189.9
190.9
3.299537
154.1
156.9
158.1
8.956298
199.5
204.4
208.4
The following figure contains the boxplots of the data from the three suppliers. It visualizes the
measure of center (median) as well as the measure of variation in the form of IQR; thus, allowing us to
compares the center of distribution as well as the consistency of the product. Regarding the need of
softness for product, the data from Supplier No.2 are most promising.
Conclusion. The data from Supplier No.3 shows the highest strength, and their variation is the largest,
indicating the least reliable. Supplier No.1 is better than No.3 in the measure of variation, and it has the
smallest standard deviation, suggesting the reliability of their product. But the boxplots indicate that the
data from No.2 are much lower than the other two suppliers, although the variation is not necessarily
the smallest. Thus, we conclude that Supplier No.2 can provide material which produces lenses having
reliably low strength.