Tutor profile: Jamie M.
Subject: Basic Math
Round 8.456 to the nearest hundreth.
The appliance manufacturer claims that its most popular refrigerator has an average useful lifetime of 15 years, with a standard deviation of 2 years. Assuming that refrigerator useful life is normally distributed, what is the probability that a randomly selected refrigerator will stop working after 18 years of use?
We know these to be true: ~the mean is 15 years ~the standard deviation is 2 years ~the normal random variable for which we want to find the cumulative probability is 18 years Using normal distribution function in Excel, we find that the cumulative probability for 18 years, P(X<= 18) is 0.93319. This means that there is a 93.3% chance that a refrigerator will die before 18 years of useful life.
Solve the following equation for x: 4x + 20 = 60
x = 10
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