Business Statistics: Describing Data
A business statistics instructor teaches a class with 83 students. Suppose he would like to create a frequency distribution to summarize their 83 final exams scores. Using the "2 to the k rule," how many classes should used?
7
When establishing a category width, assume that you have 55 raw data values, that you have determined to use 6 classes, the largest data value is 4396, and the smallest data is 308. What class interval would you use?
681
Which of the following is an advantage of a cumulative frequency polygon over a histogram or frequency polygon?
It can show the total number of observations less than a particular class' upper limit.
Which two of the following practices are commonly used in setting class limits for a frequency distributions?
Placing "excess" interval width equally in the two tails of the distribution. Rounding the class size up.
In using the "2 to the k rule" to determine the number of classes for a frequency distribution, what is the meaning of the variable k?
K is the smallest number of classes such that 2^k is greater than the number of observations
Suppose a frequency distribution has the following consecutive classes: $20 up to $30, $30 up tp $40, $40 up to $50 What is the class midpoint for the first class?
25
Suppose that the miles per gallon for 80 cars is summarized in a frequency distribution. Below is a part of a distribution. What would the relative frequency be for the class "20 up to 24?"
.20 (16/80)
PlaceList the steps used in constructing a frequency distribution into the correct order.
1. Decide on the number of classes. 2. Determine class interval. 3. Set individual class limits. 4. Tally the number of observations in each class.
Suppose you are trying to summarize a data set with a maximum value of 70 and a minimum value of 1. If you have decided to use seven classes, which one of the following would be a reasonable class interval?
10 ((70-1)/7 = 9.86, round up to 10)
Given below are the data for blood types: A B B AB O O B AB B A B O O O A O A A O A B B O AB Which is the frequency for blood type AB?
3
Refer to the following information from a frequency distribution for heights of college women recorded to the nearest inch: the first two class midpoints are 62.5" and 65.5". What are the class limits for the lowest class?
61-64
Which of the following best describes a frequency table?
A grouping of qualitative data into classes showing the number of observations in each class.
To divide data with a high value of H and a low value of L into k classes, the class interval must be:
At least (H-L)/k
Regarding frequency tables and frequency distributions, which of the following are true?
Both us mutually exclusive classes. Only frequency tables use qualitative data.
What is the final step in creating a frequency distribution?
Count the number of observations in each class.
The value shown on the vertical axis of a cumulative frequency polygon for a particular class is found by:
Counting the number of observations less than the upper limit of the class.
The number of observations in each class is called the class
Frequency
A frequency distribution table shows the number of observations for each class interval of data. How is the data plotted as a frequency polygon?
Frequency is plotted on the vertical axis and the class midpoint is plotted on the horizontal axis.
Which of the following is the best definition of "class midpoint"?
Halfway between the lower and upper limits of two consecutive classes.
Which of the following feature is an advantage that the frequency polygon has over the histogram?
It can directly compare two or more frequency distributions
Which of the following is an advantage of a frequency polygon over a histogram?
It shows class midpoints as points on a polygon
Which one of the following is not a characteristic of a frequency distribution?
It summarizes qualitative data.
A relative frequency distribution shows:
The fraction or percentage of observations in each class interval.
Which of the following can be observed from a histogram? Check all that apply?
The spread of the data The approximate number of observations The concentration of the data The shape of the distribution
Which of the following is a feature of a relative frequency distribution?
The sum of the relative frequencies must be one (assuming no rounding errors).
For a relative frequency distribution, relative frequency is computed as _____________.
class frequency divided by the total number of observations
Which of the following are characteristics of frequency tables?
No observations can fit into more than one class. They can be used for qualitative data.
Which of the following are characteristics of frequency distributions?
Organize raw data. It providers the tally for each class. Use classes and frequencies to organize data.
Which of the following feature is not part of a histogram?
The frequency of occur each of a nominal variable
Which of the following feature is not part of a histogram?
The frequency of occurrences of a nominal variable.
What informations is shown on the horizontal axis of a bar chart?
The qualitative class label.
A frequency polygon shows the shape of a distribution and is similar to:
A histogram
Which one of the following is true regarding raw data?
Raw data are simply a listing of data before summarizing it.
A pie chart shows
Relative frequencies of a qualitative variable
Which of the following operations is true regarding frequency distributions?
The relative frequency is found by dividing the class frequencies by the total number of observations.
Which of the following are characteristics of raw data?
Raw data can be either qualitative or quantitative. When the data is in its original form it is referred to as new data.
Which of the following is not a useful practice in setting individual class limits for a frequency distribution?
Excluding outliers that cause the interval to be too wide.
A business statistics course has 2 accounting majors, 4 finance majors, 6 marketing majors, and 8 insurance majors. Which of the following is true if a pie chart was constructed to depict majors of students?
The marketing slice would be three times as big as the accounting slice.
