Statistics and Maths : Assignment

Statistics and Maths
Student Name:
Student Number:
15th October 2017

Answers to Exercises 2:
A1 Ways of graphing quantitative variables;
Histogram
Scatter plot
Time series plot
Ways of graphing qualitative variables;
Bar graph
Pie-Chart
A2: According to the polygon the most common test score was 85. We can tell this because the
frequency of 85%was 140 as we can see on the y axis.
A3:
As can be seen from the side-by-side box plots, it is evident that tournament players have a
higher remembrance rate compared to other group of participants. Non-players had the least
average of pieces remembered. The number of pieces remembered increases with the level of the
player
A4: The amount of data would be the deciding factor in this case. With more data, a histogram
can be very useful since it shows the overall shape of the distribution. It, therefore, can be used
to view a large set of data efficiently. A stem and leaf display, on the other hand, is better for
smaller sets of data. Therefore, if choosing between these two methods, the main factor will be
the amount of data we are dealing with.
A5: In a box plot, the upper score is 75% and the lower score is 25%, so the percent in between
is 50%.

A6: A line graph could be appropriate, but I would choose a bar graph because we have a wide
range of countries and a bar graph would be easier to read.
A7:
a) Pie chart
b) Horizontal bar graph
c) Vertical bar graph

d) A frequency table with the relative frequency of each eye color
Eye Color Number of
students
Relative
frequency
Cumulative
frequency
Brown 11 42.3% 42.3%
Blue 10 38.5% 80.8%
Green 4 15.4% 96.2%
Gray 1 3.8% 100.0%
A8: There are many ways this bar graph could be improved such as the features added to the bars
and setting the base line to something other than zero.
A9: “B” has a large positive skew and “C” has a large negative skew.
A10:
a) Boxplot
b) Stem-and-leaf plot
Male Female
76|2|6
4|2|4
2|2|2333
10|2|001
98888|1|888888
776666|1|66677777
555554|1|444445555
2222|1|22233333
11|1|011111

9|0|99
A11:
A12:
A13:
A box-plot would be a better graphical plot since it would also provide information about the
distribution of these data.
A14:

There are no outliers in the data. Group 2 (non-athletes) on average report higher
expressions of anger.
A15:

A16:
The 25th percentile and 50th percentile are the same value.
A17:
The distribution is positively skewed.

A18:
A19:
Average weight