Over the past several months, an adult patient has been treated for tetany (severe muscle spasms). This condition is associated with an average total calcium level below 6 mg/dl. Recently, the patient's total calcium tests gave the following readings (in mg/dl). Assume that the population of x values has an approximately normal distribution. 9.1 8.4 10.3 8.7 9.4 9.8 10.0 9.9 11.2 12.1 (a) Use a calculator with mean and sample standard deviation keys to find the sample mean reading and the sample standard deviation s. (in mg/dl; round your answers to two decimal places.) = ___________ mg/dl s = __________ mg/dl (b) Find a 99.9% confidence interval for the population mean of total calcium in this patient's blood. (in mg/dl; round your answer to two decimal places.) lower limit __________ mg/dl upper limit __________ mg/dl
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!
Over the past several months, an adult patient has been treated for tetany (severe muscle spasms). This condition is associated with an average total calcium level below 6 mg/dl. Recently, the patient's total calcium tests gave the following readings (in mg/dl). Assume that the population of x values has an approximately
9.1 | 8.4 | 10.3 | 8.7 | 9.4 | 9.8 | 10.0 | 9.9 | 11.2 | 12.1 |
(a)
Use a calculator with mean and sample standard deviation keys to find the sample mean reading and the sample standard deviation s. (in mg/dl; round your answers to two decimal places.)= ___________ mg/dl
s = __________ mg/dl
(b)
Find a 99.9% confidence interval for the population mean of total calcium in this patient's blood. (in mg/dl; round your answer to two decimal places.)lower limit __________ mg/dl
upper limit __________ mg/dl
Number of samples (n) = 10
9.1 | -0.79 | 0.6241 |
8.4 | -1.49 | 2.2201 |
10.3 | 0.41 | 0.1681 |
8.7 | -1.19 | 1.4161 |
9.4 | -0.49 | 0.2401 |
9.8 | -0.09 | 0.0081 |
10.0 | 0.11 | 0.0121 |
9.9 | 0.01 | 0.0001 |
11.2 | 1.31 | 1.7161 |
12.1 | 2.21 | 4.8841 |
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