Thursday, January 10, 2013

Random Sample Example

Introduction to random sample example :

An operation which produces an outcome is known as sampling. When a select is conducted repeatedly under the same conditions the results can not be unique but may be one of the various possible outcomes. Such a select is called a random selection. In a random select, we cannot predict the outcome.In this article we study about define random sample and develop the knowledge of the random sample of the probability.I like to share this Sample Mean Formula with you all through my article.

Some Example for Random Sample:

Tossing a coin is a random selection. When we toss a coin either head or tail may rotate up. Some more examples of random experiment sample define:

Rolling die.
Drawing a card as a pack of cards.
Taking out a ball from a bag containing balls of special colo

More Example for Random Sample:

Example 1:

Number is chosen at random from 1 to 120. Get the probability that the number is divisible by 6.

Solution:

Sample space S = { 1, 2, 3, ….120 }, so n(S) = 120.

Let A denote the event of getting a number divisible by 6.

So, A = { 6, 12, 18, 24, 30, 36, 42, 48, 54,60,66,72,78,84,90,96,102,108,114,120}, n(A) = 20.

P(A) =` (n(A))/(n(S)) ` = `20/120` =` 1/6`

Is this topic hard math problems for 5th graders hard for you? Watch out for my coming posts.

Example 2:

There are 4 items defective in the access of 64 items. calculate the probability that an item selective at random from the access in sample  space is not defective.

Solution:

Total number of items n(S) = 64. Number of defective items = 4. Number of items which are not defective = 64 – 4 = 60.

Let A be the event of selecting an item which be not defective.

P(A)=`(n(A))/(n(S))` = ` 4/64 ` = `1/16`

Example 3:

Three dice are rolled once. What is the access that the sum of the face numbers on the three dice is greater than 15?

Solution:

At what time three dice are rolled, the sample space S = {(1,1,1), (1,1,2), (1,1,3) ...(6,6,6)}.

S contains 6 × 6 × 6 = 216 outcome.

Let A be the event of getting the figure of face numbers greater than 15.

A = { (4,6,6), (6,4,6), (6,6,4), (5,5,6), (5,6,5), (6,5,5), (5,6,6), (6,5,6), (6,6,5), (6,6,6)}.

n(S) = 216, n(A) = 10.

Therefore P(A)=`(n(A))/(n(S))` =`10/216` =`5/108`

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