The table below shows a frequency distribution of the lifetimes of electronic tubes produced at a factory, determine the percentage of electronic tubes with lifetimes are at least 400O hours but less than 700 hours. * Lifetime Number of (hours) Electronic Tubes 300-399 14 400-499 46 500-599 58 600-699 76 700-799 68 800-899 62 900-999 48 1000-1099 22 1100-1199 6
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 table below shows a
10
frequency distribution of the
lifetimes of electronic tubes
produced at a factory,
determine the percentage of
electronic tubes with
lifetimes are at least 400
hours but less than 700
hours. *
Lifetime
Number of
(hours)
Electronic Tubes
300-399
14
400-499
46
500-599
58
600-699
76
700-799
68
800-899
62
900-999
48
1000-1099
22
1100-1199
6](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff3743444-862e-4b7d-bf1e-33f3cd12c4b8%2F3dda3d3b-bb5d-4081-a3ce-dcb7318e90a7%2F8qvxhgq_processed.png&w=3840&q=75)
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