Data Analysis | Assignment-1

Running head: STATS 2040 1
Data Analysis Assignment
Student’s Name
Institutional Affiliation

STATS2040 2
Question 1
a.
The boxplot is a standardized way to allow one to display the data distribution that is based
on a five-number summary namely: minimum, first quartile, median, third quartile, and
maximum. Attached is the boxplot of the birth weight of 30 female African elephants
b.
The normal Q-Q plot is used to determine if a distribution is normally distributed and its
shape in general.

STATS2040 3
c.
The two plots reveal that the data is normally distributed. The points seem to lie about
the straight line fitted. The box plot is symmetric that suggests that the data follows a normal
distribution. Also, there exist no outliers since all the data plots lie within the box and
whiskers plot. The normality assumption is therefore satisfied.
d.
Below is the analysis of one sample-t-test on the weight data. The results reveal that the birth
weight of elephants lies between 89.98to 100.2 kilograms at a 95% confidence level.
One Sample t-test
data: data$weight
t = 38.054, df = 29, p-value < 2.2e-16
alternative hypothesis: true mean is not equal to 0
95 percent confidence interval:
89.97625 100.19709
sample estimates:
mean of x
95.08667
e.
The female African elephants, therefore, have an average birth weight of 95.09 kilograms. As
seen above, the birth weight of elephants lies between 89.98to 100.2 kilograms at a 95%
confidence level. This implies that if this sample was picked randomly from a population of
African female elephants born in captivity, every elephant is likely to be born weighing about
95.09 kilograms. The least likely weight and the maximum likely weight to be registered is
89.98 and 100.2 kilograms respectively.
f.
A hypothesis is defined as an educated guess and categorized into the null and alternative
hypotheses. The null hypothesis assumes no difference while the alternative carries the
researchers’ question.