Statistics and Probability Answers

A company manufactures large LCD screens knows that there is no all pixels on

their screen light, even if they spend great care when making them. In a sheet of 6 ft by

10 ft that will be cut into smaller screens, they find an average of 4.8 blank pixels. They

believe that the occurrences of blank pixels are independent. Their warranty policy

states that they will replace any screen sold that showed more than 3 blank pixels.

i. What is the mean number of blank pixels per square foot?

ii. What is the standard deviation of blank pixels per square foot?

iii. What is the probability that a 2 ft by 3 ft screen will have at least two

defects?

iv. What is the probability that a 2 ft by 3 ft screen will be replaced

because of blank pixels?

In a survey conducted, 58% of workers said that employers have the right to monitor

their smart phone use. Suppose that a random sample of 18 workers is selected, and

they are asked if employers have the right to monitor smart phone use.

i. What is the probability that 5 or more of the workers agree?

ii. What is the probability that 4 to 12 of the workers agree?

iii. What is the probability that at least 10 of the workers NOT agree?

iv. What are the mean and standard deviation of the number of workers

agree?

An urn contains 10 red and 15 blue balls.

(a) (5 points) You select 8 balls

at random without replacement. What is the probability that

exactly 5 are blue?

(b) (5 points) You select 3 balls

at random without replacement. What is the probability that

exactly two are the same color?

(c) You select 3 balls

at random without replacement. You find that exactly two are the same color.

What is the conditional probability that the two that are the same color are both blue?

• A researcher measured behavior among all individuals in some small population. Are inferential statistics necessary to draw conclusions concerning this population? Explain

There are 12 people waiting for extra tickets to a comedy show. Three tickets become available and are randomly assigned. How many different groupings of people can be given the tickets? What is the probability you and your two friends are the 3 people that receive the tickets?

Amira knows that the time it takes her to commute to work is approximately normally distributed with a mean of 45 minutes and a standard deviation of 3 minutes. What time must she leave home in the morning so that she is 95% sure of arriving at work by 9.00am? 

In testing a certain kind of truck tire over a rugged terrain, it is found that 25% of the trucks fail to complete the test run without a blowout. Of the next 15 trucks tested, find the probability that a) From 3 to 6 have blowouts; b) Fewer than 4 have blowouts; c) More than 5 have blowouts.

. In the same carnival, there is a similar game of chance. The game involves a small bag containing 30 marbles where 12 are green, 8 are yellow, and the rest are brown. You win Php 20.00 if you are able to draw a green marble, and you win Php 10.00 if you are able to draw a yellow marble. You lose Php 30.00 if you are able to draw a brown ball. If you continue to play the game, how much do you expect to win or lose in the game

phone call arrive at the rate of 48 per our at the reservation desk for sri lankan airways.Find the probability of receiving three call in a five minute interval of time

(b)  3 Cards are drawn in succession without replacement from an ordinary deck. Find the probability of the event A1 ∩ A2 ∩ A3, where A1 is the event that the first card is RED ace, A2 is the event that the second card Queen or King and A3 is the event that the third card which is greater than 3 and less than Eight ?