Math Answers

An electrical firm manufactures light bulbs that have a length of life that is normally distributed with mean equal to 817 hours and a standard deviation of 48 hours. Find the probability that a bulb burns between 736 and 823 hours.

Given a standard normal distribution with mean =61 and standard deviation = 35, find P(X<113)

Given a standard normal distribution with mean =101 and standard deviation = 43, find P(X>145)

Given a standard normal distribution with mean =105 and standard deviation = 28, find P(72 < X < 111)

Given the μ = 43.66 and σ = 1.03, compute the z-score that corresponds to the given score X = 37

Given the μ = 24 and σ = 3, compute the z-score that corresponds to the given score X = 39

If the effective rate of interest is compounded quarterly is 16%, then the nominal rate of interest is

The time taken to assemble a car in certain plant is a random variable having a normal distribution of 20 hours and a standard deviation of 2 hours. What is the probability the car can be assembled at this plant in a period of time

a) less than 19.5 hours?

b) between 20 and 22 hours?

Prove that √(1+√3) is irrational, assuming that √3 is irrational

15. Let

f(x,y) { 0, x² < y < 2x² 1. otherwise

Verify the existence of partial derivatives fr(0,0) and f(0, 0), and the differentiability of fat (0,0).