Let X denote the courtship time for a randomly selected female-male pair of mating scorpion flies (time from the beginning of interaction until mating). Suppose the mean value of X is 120 min and the standard deviation of X is 110 min (suggested by data in the article "Should I Stay or Should I Go? Condition- and Status-Dependent Courtship Decisions in the Scorpion Fly Panorpa Cognate"†). (a) Is it plausible that X is normally distributed? a)Yes, courtship time is plausibly normally distributed since the mean of X is larger than 100. b)No, courtship time cannot plausibly be normally distributed. Since X must be non-negative, realistically the interval μ ± 3σ should be entirely non-negative which is not true in this case. c)Yes, courtship time is plausibly normally distributed. Since X must be non-negative, realistically the interval μ ± 3σ should be entirely non-negative which is true in this case. d)Yes, courtship time is plausibly normally distributed. Since X must be negative, realistically the interval μ ± 3σ should be entirely negative which is true in this case.
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!
Trending now
This is a popular solution!
Step by step
Solved in 3 steps with 4 images