Conditional Probability Word Problems

**Page 1**

1.

Select the statements related to descriptive statistics.

I. collection of data

II. organization and summarization of data

III. presentation of data

IV. determine relationships among variables of the data

I. collection of data

II. organization and summarization of data

III. presentation of data

IV. determine relationships among variables of the data

a. | I and II only | ||

b. | II and III only | ||

c. | I, II and III only | ||

d. | all are correct |

Inferential statistics determines the relationship between the variables of the data.

So, only I, II and III are related to descriptive statistics.

Correct answer : (3)

2.

Statistics find use in determining relationships among variables. Which of the following represent such cases?

I. use of coconut oil and heart attack

II. lung cancer and smokers

III. number of accidents on a highway

IV. monthly salary and annual salary

I. use of coconut oil and heart attack

II. lung cancer and smokers

III. number of accidents on a highway

IV. monthly salary and annual salary

a. | I only | ||

b. | I and II only | ||

c. | I, II and III only | ||

d. | all are correct |

The chances of getting lung cancer due to smoking can be determined using statistical study.

Number of accidents on highway is only a data. There is no relationship between variables involoved in this case.

There is a direct relation between monthly salary and annual salary. There is no need for a statistical study in this case.

So, only I and II are correct.

Correct answer : (2)

3.

Which of the following are true for inferential statistics?

I. generalises from samples to population

II. uses probability

III. performs estimations and hypothesis to statistics

IV. makes predictions

I. generalises from samples to population

II. uses probability

III. performs estimations and hypothesis to statistics

IV. makes predictions

a. | only I and III | ||

b. | only II and IV | ||

c. | only II, III and IV | ||

d. | all are correct |

Samples of the population are used for study.

Analysis is done through estimation, hypothesis tests, etc.

For making inferences or predictions, probability techniques are applied.

So, all the statements are correct.

Correct answer : (4)

4.

Select the statements where descriptive statistics is used.

I. Increase in the annual sales of hamburgers in the district was 30% of the sales of previous year.

II. Infant morality rate in an underdeveloped country registered a drop of 10% during the last decade.

III. Defence accounted 30% of the annual budget for the year2003 - 2004.

IV. There are 1200 regular users of internet in a school of 2000 students.

I. Increase in the annual sales of hamburgers in the district was 30% of the sales of previous year.

II. Infant morality rate in an underdeveloped country registered a drop of 10% during the last decade.

III. Defence accounted 30% of the annual budget for the year

IV. There are 1200 regular users of internet in a school of 2000 students.

a. | I, II and III only | ||

b. | I, III and IV only | ||

c. | IV only | ||

d. | all are correct |

Correct answer : (4)

5.

Select the statements where inferential statistics is used.

I. The average annual salary of a software engineer in the age group of23 - 25 is $50,000.

II. Increase in the price of steel from1990 to 1995 was 37%.

III. The number of students getting enrolled in a university increases 10% every year.

IV. Number of mobile telephone connections in the country increased 20 times during the past5 years.

I. The average annual salary of a software engineer in the age group of

II. Increase in the price of steel from

III. The number of students getting enrolled in a university increases 10% every year.

IV. Number of mobile telephone connections in the country increased 20 times during the past

a. | I only | ||

b. | II and III only | ||

c. | all are correct | ||

d. | none of these |

The cases of inferential statistics is none.

Correct answer : (4)

6.

Select the statements according to descriptive statistics (D) or inferential statistics (I).

1. 40 out of 100 heart patients admitted in a hospital were smokers.

2. Usage of a particular drug would reduce the number of heart attacks in the age group of45 - 50 years.

3. The chances of getting a defective TV from a batch of 500 TV's dispatched from a manufacturing unit is 0.02.

1. 40 out of 100 heart patients admitted in a hospital were smokers.

2. Usage of a particular drug would reduce the number of heart attacks in the age group of

3. The chances of getting a defective TV from a batch of 500 TV's dispatched from a manufacturing unit is 0.02.

a. | 1 - D, 2 - D, 3 - I | ||

b. | 1 - D, 2 - I, 3 - I | ||

c. | 1 - I, 2 - I, 3 - I | ||

d. | 1 - I, 2 - I, 3 - D |

Statement 2 is made after study of a sample and arriving at an inference. It is inferential statistics.

Statement 3 is also a result of sampling and infering the result. It is also inferential statistics.

Correct answer : (2)

7.

Select the areas where probability is used.

I. insurance industry

II. end of the course examinations

III. weather predictions

IV. baseball game

I. insurance industry

II. end of the course examinations

III. weather predictions

IV. baseball game

a. | all are correct | ||

b. | I and III only | ||

c. | III and IV only | ||

d. | I, III and IV only |

In the end of the course examinations, each answer sheet is valued. So there is no application of probability in this area.

Weather prediction applies probability theory.

Baseball game is a sport and not gambling. There is no application of probability in this game.

Correct answer : (2)

8.

Select the wrong statement(s).

I. Two major branches of statistics are statistics and probability.

II. A group of all subjects under study is called a population.

III. Statistics is the science of conducting studies to collect, organize, summarize, analyze and draw conclusions from data.

I. Two major branches of statistics are statistics and probability.

II. A group of all subjects under study is called a population.

III. Statistics is the science of conducting studies to collect, organize, summarize, analyze and draw conclusions from data.

a. | I only | ||

b. | II only | ||

c. | I and II only | ||

d. | all are wrong |

So, statement I is wrong.

Correct answer : (1)

9.

Select the qualitative variables.

I. School districts participating in the competition

II. Countries from which films are nominated for oscar awards

III. Religions represented in the ceremony

IV. Aggregate score of each student

I. School districts participating in the competition

II. Countries from which films are nominated for oscar awards

III. Religions represented in the ceremony

IV. Aggregate score of each student

a. | all | ||

b. | I and III only | ||

c. | II and III only | ||

d. | I, II and III only |

Variables under I, II and III are qualitative variables.

Correct answer : (4)

10.

Select the quantitative variables.

I. Monthly sales of each type of TV

II. Goals scored by each team in world cup soccer

III. Color of jerseys of each team in world cup soccer

IV. Medals won by each country in olympics

I. Monthly sales of each type of TV

II. Goals scored by each team in world cup soccer

III. Color of jerseys of each team in world cup soccer

IV. Medals won by each country in olympics

a. | I, II and III only | ||

b. | I, II and IV only | ||

c. | II, III and IV only | ||

d. | all |

Variables under I, II and IV are quantitative variables.

Correct answer : (2)