Archive for the ‘Motorcycle Helmet Parts’ Category
Vintage Motorcycle Parts
http://www.vintage-motorcycle-parts.net - ultimate vintage motorcycle parts website. Music: Kevin MacLeod http://incompetech.com Commercial: http://www.aliksandco.com
Duration : 32 sec
optimus prime helmet
not peter cullens voice. from the first movie. 2 yellow led headlights. chipcorder triggered by key switch and button. leds light up in mouth.
Duration : 55 sec
Trouble with Normal Probability Distribution; How do I get these answers!!?
1. During the past 40 years, the monthly rate of return of stocks has been approximately normally distributed, with µ = .75% and σ = 4.2%, according to data obtained from Yahoo Finance.
a. What is the probability that a randomly selected month has a rate of return of at least 1%?
b. What is the probability that a randomly selected month has a rate of return less than 2%.
c. What proportion of months have a positive rate of return? (hint:positive means greater than 1)
d. In March, 2000, the monthly rate of return on stocks was 9.7%. Is this rate of return unusual? Support your answer.
2. Engineers must consider the breadth of male heads when designing Motorcycle Helmets. Men have head breadth that are normally distributed with a mean of 6 inches and a standard deviation of 1 inch.
a. If one male is randomly selected, find the probability that his head breadth is less than 6.2 inches.
b. The Safeguard Helmut Company plans an initial production run of 100 helmets. Find the probability that 100 randomly selected men have a mean head breadth of less than 6.2 inches.
c. The production manager sees the result from Part b and reasons that all helmets should be made for men with head breadths less than 6.2 inches, because they would fit all but a few men. What is wrong with this reasoning?
1a. P(X < 0.01) = P((x - 0.0075) / 0.042) < (0.01 - 0.0075) / 0.042) = P(Z < 0.06) = 0.5237
P(X > 0.0075) = 1 - 0.5237 = 0.4763
1b. P(X < 0.02) = P((x - 0.0075) / 0.042) < (0.02 - 0.0075) / 0.042) = P(Z < 0.30) = 0.6170
1c. Positive means greater than zero:
P(X < 0.0) = P((x - 0.0075) / 0.042) < (0.0 - 0.0075) / 0.042) = P(Z < -0.18) = 0.4291
P(X > 0.0) = 1 - 0.4291 = 0.5709
1d. P(X >= .097) = .0165 is unusual