chapter 2 MAT 152 LN1 Summer 2017 Carr
Constructing a frequency Distribution
1. Decide on the # of classes (between 5 and 20) 2. Find the class width as follows a, divide the range by the # of classes. b. round up to the next convenient # 3. Find the class limits 4. Find the frequency
Determine whether the statement is true or false. If it is false, rewrite it as a true statement. In a frequency distribution, the class width is the distance between the lower and upper limits of a class. Choose the correct answer below.
False. In a frequency distribution, the class width is the distance between the lower or upper limits of consecutive classes.
What are some benefits of representing data sets using frequency distributions? What are some benefits of using graphs of frequency distributions? What are some benefits of representing data sets using frequency distributions? What are some benefits of using graphs of frequency distributions?
Organizing the data into the frequency distribution can make patterns within the data more evident. It can be easier to identify patterns of a data set by looking at a graph of the frequency distribution.
Use the given minimum and maximum data entries, and the number of classes, to find the class width, the lower class limits, and the upper class limits. minimumequals 7, maximumequals 95, 6 classes Choose the correct lower class limits below. Choose the correct upper class limits below.
The class width is 15 7,22,37,52,67,82 21,36,51,66,81
Use the given minimum and maximum data entries, and the number of classes to find the class width, the lower class limits, and the upper class limits. minimumequals 11, maximumequals 98, 6 classes
Use the given minimum and maximum data entries, and the number of classes to find the class width, the lower class limits, and the upper class limits. minimumequals 11, maximumequals 98, 6 classes Each class has a lower class limit, which is the least number that can belong to the class, and an upper class limit, which is the greatest number that can belong to the class. The class width is the distance between lower (or upper) limits of consecutive classes. The difference between the maximum and minimum data entries is called the range. Find the class width as follows. Determine the range of the data, then divide the range by the number of classes and round up to the next convenient number. The range of the data is 98 minus11equals87 . Divide the range by the number of classes. StartFraction 87 Over 6 EndFraction equals14.5 The next convenient number 15 , is the class width. Use the minimum data entry as the lower limit of the first class. To find the remaining lower limits, add the class width to the lower limit of the preceding class. The lower class limits are 11, 26, 41, 56, 71, 86 . The upper limit of the first class is one less than the lower limit of the second class. The upper limit of the first class is 25 . To find upper limits of the other classes, add the width of the class to the upper limit of the previous class. Remember that classes cannot overlap. The upper limits are 25 , 40 , 55 , 70 , 85 , 100 . Thus, the class width is 15 , the lower class limits are 11 , 26 , 41 , 56 , 71 , 86 and upper class limits are 25 , 40 , 55 , 70 , 85 , 100 .
Frequency distribution
a table that shows classes or intervals of data entries in each class
range
the difference between the maximum and the minimum data entries.
class width
the distance between lowr (or upper) limits of consecutive classes.
class limits
the least and greatest number that can belong in a class.
Relative Frequency
the portion or percentage of the data tha falls in that class = (class freq)/( sample size) sum should equal 1
Cumulative Frequency
the sum of the frequencies of that class and all previous classes.
midpoint of the class
the sum of the lower and upper limits of the class divided by 2
Class boundaries
the# that separate classes w/o forming gaps between them
What is the difference between relative frequency and cumulative frequency? Choose the correct answer below
A. Relative frequency of a class is the percentage of the data that falls in that class, while cumulative frequency of a class is the sum of the frequencies of that class and all previous classes.
After constructing a relative frequency distribution summarizing IQ scores of college students, what should be the sum of the relative frequencies? Choose the correct answer below
After constructing a relative frequency distribution summarizing IQ scores of college students, what should be the sum of the relative frequencies? Choose the correct answer below
Frequancy (f) of a class
the # of data entries in the class.
