Question

2. The following data on distilled alcohol content (%) for a sample of 35 port wines was extracted from the
article “A Method for the Estimation of Alcohol in Fortified Wines Using Hydrometer Baumé and
Refractometer Brix” (Amer. J. Enol. Vitic., 2006: 486–490). Each value is an average of two duplicate
measurements.
16.35 18.85 16.20 17.75 19.58 17.73 22.75 23.78 9.12 10.22 23.25 19.08 19.62 33.05 19.20 20.05 17.85 19.17
19.48 20.00 19.97 42.13 11.42 03.28 41.56 17.48 17.15 19.07 19.90 18.68 18.82 19.03 19.45 19.37 19.20 18.00
19.60 19.33 21.22 19.50 15.30 22.25
a. Draw a stem and leaf plot of these data.
b. Group the data into class intervals and draw the resulting relative frequency histogram.
c. Determine the sample mean, median and mode.
d. Determine the variance, SD, and range.
e. Determine the quartile 1 (Q1), quartile 2 (Q2), quartile 3 (Q3)
f. Determine the IQR and outliers.
g. Determine the 5-number-summary and draw the corresponding boxplot.

Answer 1

a. Draw a stem and leaf plot of these data.

b. Group the data into class intervals and draw the resulting relative frequency histogram.

Formula Ref:

c. Determine the sample mean, median and mode.

Formula Ref:

d. Determine the variance, SD, and range

Formula Ref:

e,f, and g:

e. Determine the quartile 1 (Q1), quartile 2 (Q2), quartile 3 (Q3)

Q1 = 17.78

Q2: 19.20

Q3: 19.95

Determine the IQR and outliers.

IQR: 2.18

Outliers:

There are 9 outliers

3.28

9.12

10.22

11.42

23.25

23.78

33.05

41.56

42.13

Determine the 5-number-summary and draw the corresponding boxplot.

Formula Ref: