**Percentage Frequency of a Class Interval : **

Percent frequency of a class interval may be defined as the ratio of class frequency to the total frequency, expressed as a percentage.

To have better understanding on percentage frequency of a class interval, let us consider the frequency distribution given below.

In the above frequency distribution of weights of 36 students, the percentage frequencies for the first two class intervals are 300/36 and 400/36 respectively.

Apart from percent frequency of a class interval, let us look at some other important terms associated with a frequency distribution.

Relative frequency of a class interval may be defined as the ratio of the class frequency to the total frequency.

In the above frequency distribution of weights of 36 students, the relative frequencies for the first two class intervals are 3/36 and 4/36 respectively.

It is quite obvious that whereas the relative frequencies add up to unity, the percentage frequencies add up to one hundred.

It may be defined as the ratio of the frequency of that class interval to the corresponding class length.

In the above frequency distribution of weights of 36 students, the frequency densities for the first two class intervals are

3/5 and 4/5

That is, 0.60 and 0.80 respectively.

To understand class limit and class boundary in statistics, let us consider the frequency distribution of weights of 36 students given below.

Corresponding to a class interval, the class limits may be defined as the minimum value and the maximum value the class interval may contain.

The minimum value is known as the lower class limit (LCL) and the maximum value is known as the upper class limit (UCL).

For the frequency distribution of weights of 36 students, the LCL and UCL of the first class interval are 44 kgs. and 48 kgs. respectively.

Class boundaries may be defined as the actual class limit of a class interval.

For overlapping classification or mutually exclusive classification that excludes the upper class limits like 10–

20, 20–30, 30–40, ……… etc. the class boundaries coincide with the class limits.

This is usually done for a continuous variable. However, for non-overlapping or mutually inclusive classification that includes both the class limits like 0–9, 10–19, 20–29,…… which is usually applicable for a discrete variable, we have

where D is the difference between the LCL of the next class interval and the UCL of the given class interval.

For the data presented in the above table, LCB of the first class interval

and the corresponding UCB

Apart from the stuff class limit and class boundary, let us look at the mid point of a class interval.

Corresponding to a class interval, this may be defined as the total of the two class limits or class boundaries to be divided by 2.

In other words, in a class interval, mid point or mid value may be defined as arithmetic mean or average of the two class limits and two class boundaries.

Thus, we have

Referring to the distribution of weight of 36 students, the mid-points for the first two class intervals are

That is, 46 kgs. and 51 kgs. respectively.

After having gone through the stuff given above, we hope that the students would have understood, the stuff percentage frequency of a class interval.

Apart from the stuff given on this web page, if you need any other stuff in math, please use our google custom search here.

Widget is loading comments...

You can also visit our following web pages on different stuff in math.

**WORD PROBLEMS**

**Word problems on simple equations **

**Word problems on linear equations **

**Word problems on quadratic equations**

**Area and perimeter word problems**

**Word problems on direct variation and inverse variation **

**Word problems on comparing rates**

**Converting customary units word problems **

**Converting metric units word problems**

**Word problems on simple interest**

**Word problems on compound interest**

**Word problems on types of angles **

**Complementary and supplementary angles word problems**

**Markup and markdown word problems **

**Word problems on mixed fractrions**

**One step equation word problems**

**Linear inequalities word problems**

**Ratio and proportion word problems**

**Word problems on sets and venn diagrams**

**Pythagorean theorem word problems**

**Percent of a number word problems**

**Word problems on constant speed**

**Word problems on average speed **

**Word problems on sum of the angles of a triangle is 180 degree**

**OTHER TOPICS **

**Time, speed and distance shortcuts**

**Ratio and proportion shortcuts**

**Domain and range of rational functions**

**Domain and range of rational functions with holes**

**Graphing rational functions with holes**

**Converting repeating decimals in to fractions**

**Decimal representation of rational numbers**

**Finding square root using long division**

**L.C.M method to solve time and work problems**

**Translating the word problems in to algebraic expressions**

**Remainder when 2 power 256 is divided by 17**

**Remainder when 17 power 23 is divided by 16**

**Sum of all three digit numbers divisible by 6**

**Sum of all three digit numbers divisible by 7**

**Sum of all three digit numbers divisible by 8**

**Sum of all three digit numbers formed using 1, 3, 4**

**Sum of all three four digit numbers formed with non zero digits**