Suppose we want to study the errors found in the performance of a simple task. We ask a largenumber of judges to report the number of people seen entering a major department store inone morning. Some judges will miss some people, and some will count others twice, so wedo not expect everyone to agree. Suppose we find that the mean number of shoppers reported is975 with a standard deviation of 15. Assume that the distribution of counts is normal. What percentage of the counts will lie between 960 and 990? What percentage of the counts will lie below 975? c.What percentage of the counts will lie below 990?
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!
- Suppose we want to study the errors found in the performance of a simple task. We ask a largenumber of judges to report the number of people seen entering a major department store inone morning. Some judges will miss some people, and some will count others twice, so wedo not expect everyone to agree. Suppose we find that the mean number of shoppers reported is975 with a standard deviation of 15. Assume that the distribution of counts is normal.
- What percentage of the counts will lie between 960 and 990?
- What percentage of the counts will lie below 975?
c.What percentage of the counts will lie below 990?
Trending now
This is a popular solution!
Step by step
Solved in 3 steps with 3 images
