This cumulative review problem uses material from Chapters 3, 5, and 10. Recall that the Poisson distribution deals with rare events. Death from the kick of a horse is a rare event, even in the Prussian army. The following data are a classic example of a Poisson application to rare events. The data represent the number of deaths from the kick of a horse per army corps per year for 10 Prussian army corps over a period of time. Let x represent the number of deaths and f the frequency of x deaths. x 0 1 2 3 or more f 113 62 21 4 (a) First, we fit the data to a Poisson distribution. The Poission distribution states P(x) = e−??x x!, where ? ≈ x (sample mean of x values). From our study of weighted averages, we get the following. (b) Now we have P(x) = e−0.58(0.58)x x! for x = 0, 1, 2, 3 . Find P(0), P(1), P(2), and P(3 ≤ x). Round to three places after the decimal. P(0) = P(1) = P(2) = P(3 ≤ x) = (c) The total number of observations is Σf = 200. For a given x, the expected frequency of x deaths is 200P(x). The following table gives the observed frequencies O and the expected frequencies E = 200P(x). x 0 = f E = 200P(x) 0 113 200(0.560) = 112 1 62 200(0.325) = 65 2 21 200(0.094) = 18.8 3 or more 4 200(0.021) = 4.2 Compute ?2 = Σ (O − E)2 E using the values in the table. (Round your answer to two decimal places.)
Contingency Table
A contingency table can be defined as the visual representation of the relationship between two or more categorical variables that can be evaluated and registered. It is a categorical version of the scatterplot, which is used to investigate the linear relationship between two variables. A contingency table is indeed a type of frequency distribution table that displays two variables at the same time.
Binomial Distribution
Binomial is an algebraic expression of the sum or the difference of two terms. Before knowing about binomial distribution, we must know about the binomial theorem.
This cumulative review problem uses material from Chapters 3, 5, and 10. Recall that the Poisson distribution deals with rare events. Death from the kick of a horse is a rare
x | 0 | 1 | 2 | 3 or more |
f | 113 | 62 | 21 | 4 |
The Poission distribution states
e−??x |
x! |
e−0.58(0.58)x |
x! |
P(0) | = | |
P(1) | = | |
P(2) | = | |
P(3 ≤ x) | = |
(c) The total number of observations is
For a given x, the expected frequency of x deaths is
The following table gives the observed frequencies O and the expected frequencies
x | 0 = f | E = 200P(x) |
0 | 113 | 200(0.560) = 112 |
1 | 62 | 200(0.325) = 65 |
2 | 21 | 200(0.094) = 18.8 |
3 or more | 4 | 200(0.021) = 4.2 |
Compute
(O − E)2 |
E |
using the values in the table. (Round your answer to two decimal places.)
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