Written Assignment Unit 2: Sampling and Data Structures
University of the People
MATH 1280-01 Introduction to Statistics
Rand Alfaris, Instructor
February 7, 2023
1. According to the American Museum of National History (n.d.), “Sepal: The outer parts
of the flower (often green and leaf-like) that enclose a developing bud. Petal: The parts
of a flower that are often conspicuously colored.”
2. The correct answer is (d) Of all the flowers measured in this sample 35% had a petal
length of 3 or less (after rounding the petal lengths).
3. Value 4 and 5 at a relative frequency of 0.23.
4.
1) 0.16
2) 0.33 - 0.16 = 0.17
3) 0.35 - 0.33 = 0.02
4) 0.58 - 0.33 = 0.23
5) 0.81 - 0.58 = 0.23
6) 0.97 - 0.81 = 0.16
7) 1.0
5.
Command >>> names(flower.data)
Output >>> "Sepal.Length" "Sepal.Width" "Petal.Length" "Petal.Width" "Species"
6.
The number of observations in the "flower.data" data frame is: 150.
7.
The name and type of the 1st variable: Sepal.Length: numeric
The name and type of the 2nd variable: Sepal.Width: numeric
The name and type of the 3rd variable: Petal.Length: numeric
The name and type of the 4th variable: Petal.Width: numeric
The name and type of the 5th variable: Species: factor
8.
The frequency of the value 7: 24
9.
The sum of the first three frequencies in the frequency table for sepal width: 8
10.
It means that there are 8 frequencies with a sepal width of 2.3 or less, meaning that 8
out of 150 frequencies satisfy this condition, which corresponds to a ratio of 5.33%.
11.
The sum of the last three frequencies in the frequency table for sepal width: 3
12.
Flowers in the sample had sepal widths less than 4: 146
13.
The tallest bar in the plot represents the mode.
14.
Command >>> table (flower.data$Species)
Output >>>
setosa versicolor virginica
50
50
50
15.
a) The first row of the table shows words as we called to print the species which are
factors or qualitative.
b) The numbers in the second row of the table represent that there are 50 observations
or rows for each species.
References
American Museum of National History. (n.d.). Parts of a Flower. https://www.amnh.org/
learn-teach/curriculum-collections/biodiversity-counts/plant-identification/plantmorphology/parts-of-a-flower.