How To Identify Class Boundaries

Course LIMITS AND Class BOUNDARIES IN STATISTICS

To understand course limit and class boundary in statistics, let u.s. consider the frequency distribution of weights of 36 students given beneath.

Class Limit

Corresponding to a course interval, the form limits may exist divers equally the minimum value and the maximum value the grade 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 course interval are 44 kgs. and 48 kgs. respectively.

Class Boundary

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

For overlapping classification or mutually exclusive classification that excludes the upper class limits like 1

0 – 20, 20 – 30, 30 – forty, ……… etc.

the course boundaries coincide with the class limits.

This is usually washed for a continuous variable. Nevertheless, for not-overlapping or mutually inclusive classification that includes both the class limits like

0 – nine, 10 – 19, 20 – 29,……

which is usually applicable for a detached variable, we accept

LCB = LCL - D/2

and

UCB = UCL + D/ii

where D is the difference betwixt the LCL of the side by side grade interval and the UCL of the given class interval.

For the data presented in the above tabular array, LCB of the first form interval is

= 44 - (49 - 48)/2

= 44 - 1/ii

= 44 - 0.5

= 43.5

and the corresponding UCB is

= 48 + (49 - 48)/2

= 48 + 1/2

= 48 + 0.five

= 48.v

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

Mid Point or Mid Value or Class Mark

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

In other words, in a class interval, mid indicate or mid value may be defined as arithmetic mean or average of the two class limits and 2 class boundaries.

Thus, we take

Mid-bespeak = (LCL + UCL) / two

Mid-point = (LCB + UCB) / 2

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

(44 + 48) / ii(49 + 53) / 2

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