The University of Maryland Medical Center considers “low birth weights” to be those that are less than 2495 g. Birth weights are normally distributed with a mean of 3152.0 g and a standard deviation of 693.4 g. If a birth weight is randomly selected, what is the probability that it is a “low birth weight”? Round to four decimal places. <insert the Excel command> <insert the numerical value> If a sample of ten birth weights is randomly selected, what is the probability that the sample mean is a “low birth weight”? Round to four decimal places. <insert the Excel command> <insert the numerical value> What is the 99th percentile birth weight (in grams)? Round to one decimal places. <insert the Excel command> <insert the numerical value>
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!
- The University of Maryland Medical Center considers “low birth weights” to be those that are less than 2495 g. Birth weights are
normally distributed with a mean of 3152.0 g and a standard deviation of 693.4 g.
- If a birth weight is randomly selected, what is the
probability that it is a “low birth weight”? Round to four decimal places.
<insert the Excel command>
<insert the numerical value>
- If a sample of ten birth weights is randomly selected, what is the probability that the sample mean is a “low birth weight”? Round to four decimal places.
<insert the Excel command>
<insert the numerical value>
- What is the 99th percentile birth weight (in grams)? Round to one decimal places.
<insert the Excel command>
<insert the numerical value>
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