Chapter 2.1 Practice

Descriptive Statistics: Practice 1

Student Learning Outcomes:

The student will calculate and interpret the center, spread, and location of the data.
The student will construct and interpret histograms an box plots.
Given:

Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people answered that they generally sell three cars; nineteen generally sell four cars; twelve generally sell five cars; nine generally sell six cars; eleven generally sell seven cars.
Complete the Table
Complete the table below using the data provided.
Data Value (# cars)
Frequency
Relative Frequency
Cumulative Relative Frequency

Discussion Questions
Exercise 1
What does the frequency column sum to? Why?

Exercise 2
What does the relative frequency column sum to? Why?

Exercise 3
What is the difference between relative frequency and frequency for each data value?

Exercise 4
What is the difference between cumulative relative frequency and relative frequency for each data value?

Enter Data
Enter your data into your calculator or computer.

Construct a Histogram
Determine appropriate minimum and maximum x and y values and scaling. Sketch the histogram below. Label the horizontal and vertical axes with words. Include numerical scaling.

Data Statistics
Calculate the following values:

Exercise 5
Sample Mean =

Exercise 6
Sample standard deviatons = sx =

Exercise 7
Sample size = n =

Calculations
Use the table in section 2.11.13 to calculate the following values:

Exercise 8
Median =

Exercise 9
Mode =

Exercise 10
First quartile =

Exercise 11
Second quartile = median = 50th percentile =

Exercise 12
Third quartile

Exercise 13
Interquartile range (IQR) = _______ - _______ = ________

Exercise 14
10th percentile =

Exercise 15
70th percentile =

Exercise 16
Find the value that is 3