5 of 1 The life span of light bulbs is approximately normally distributed. Some statistics about life spans of two difforent types of light bulbs are LED bulbs: mean = 2,300 days, standard deviation 230 days incandescent bulbs: mean 100 days, standard deviation = 10 days Estimate the proportion of LED bulbs that are expected to burn out in the interval between 1 standard doviation less than the mean and 1 standard deviation greater than the mean (between 2,070 and 2,530 days). Estimate the proportion of incandescent bulbs expectod to burn out in the interval between 1 standard deviation less than the mean and 1 standard deviation greater than the mean (between 90 and 110 days). Estimate the proportion of LED bulbs that are expected to burn out in the interval between 2 standard deviations less than the mean and 2 standard deviations greater than the mean (between 1,840 and 2,760 days). Estimate the proportion of LED bulbs that are expected to burn out in the interval betwoen 1,900 days and 2,100 days.

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Q: ticular fruits weight are normally distributed with a mean of 285 grams and a standard deviation of…

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Q: What proportion of people has diastolic blood pressure less than 80?

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Continuous Probability Distributions

Probability distributions are of two types, which are continuous probability distributions and discrete probability distributions. A continuous probability distribution contains an infinite number of values. For example, if time is infinite: you could count from 0 to a trillion seconds, billion seconds, so on indefinitely. A discrete probability distribution consists of only a countable set of possible values.

Normal Distribution

Suppose we had to design a bathroom weighing scale, how would we decide what should be the range of the weighing machine? Would we take the highest recorded human weight in history and use that as the upper limit for our weighing scale? This may not be a great idea as the sensitivity of the scale would get reduced if the range is too large. At the same time, if we keep the upper limit too low, it may not be usable for a large percentage of the population!