Question

Records pertaining to the monthly number of job-related injuries at an underground coal mine were being...

Records pertaining to the monthly number of job-related injuries at an underground coal mine were being studied by a federal agency. The values for the past 100 months are given (see file H9.xlsx, sheet P3).

Apply the chi-square test to the data to test the hypothesis that the underlying distribution is Poisson. Use a level of significance of a = 0.05.

Apply the chi-square test to the data to test the hypothesis that the underlying distribution is Poisson with mean 1.0. Use a level of significance of a = 0.05.

Note that in (a) you have to estimate mean and then perform the hypothesis test, whereas in (b) you are being asked to test the hypothesis with the given mean, which may be different from the sample mean. Think carefully about the number of degrees of freedom that you will be using in (a) and (b).

Injuries per month Frequency of Occurrence
0 35
1 40
2 13
3 6
4 4
5 1
6 1

Homework Answers

Answer #1

Part A) H_0: poisson distribution vs H_a: not poisson distribution

x = 0:6
f = c(35,40,13,6,4,1,1)
p = c(.35,.4,.13,0.06,0.04,0.01,0.01)
part.a = chisq.test(x,p)
part.a

Pearson's Chi-squared test

data: x and p
X-squared = 35, df = 30, p-value = 0.2426

so failed to reject H_0

part B)

Ho:poisson dist

H_a: not poisson dist

mean = lambda = xbar

prob.poisson = function(x){
100*((exp(-m)*m^x)/factorial(x))
}
p_0=prob.poisson(0)
p_1=prob.poisson(1)
p_2 =prob.poisson(2)
p_3 =prob.poisson(3)
p_4 =prob.poisson(4)
p_5=prob.poisson(5)
p_6 =prob.poisson(6)
pnew=c(p_0,p_1,p_2,p_3,p_4,p_5,p_6)
part.b = chisq.test(x,pnew)
part.b

Pearson's Chi-squared test

data: x and pnew

X-squared = 42, df = 36, p-value = 0.227

accept Ho

x follow poisson distribution with mean 1.11

Note: degrees of freedom

in part a we have df=30 and part b df =36

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Given the following Hypotheses: Null: An equal number of fruits is distributed per consumer box Alt:...
Given the following Hypotheses: Null: An equal number of fruits is distributed per consumer box Alt: An unequal number of fruits is distributed in each box Coconut 21 Raspberry 34 Banana 33 Avocado 0 Orange 30 Starfruit 14 Total: 132 Mean: 22 SD: 2.6 Find the degrees of freedom and chi Square analysis. What is the value of chi-square needed for statistical significance at a 0.05 level for the data? I am struggling to find the correct chi square for...
MC Qu. 45 A real estate company is analyzing the... A real estate company is analyzing...
MC Qu. 45 A real estate company is analyzing the... A real estate company is analyzing the selling prices of residential homes in a given community. 140 homes that have been sold in the past month are randomly selected and their selling prices recorded. The statistician working on the project has stated that in order to perform various statistical tests, the data must be distributed according to a normal distribution. In order to determine whether the selling prices of homes...
A new kind of typhoid shot is being developed by a medical research team. The old...
A new kind of typhoid shot is being developed by a medical research team. The old typhoid shot was known to protect the population for a mean time of 36 months, with a standard deviation of 3 months. To test the time variability of the new shot, a random sample of 25 people were given the new shot. Regular blood tests showed that the sample standard deviation of protection times was 1.5 months. Using a 0.05 level of significance, test...
A statement about a population parameter that is subject to verification is a/an: Probability Density Function...
A statement about a population parameter that is subject to verification is a/an: Probability Density Function    Normal Distribution Hypothesis Critical Value   Average Mean    The p-value in Hypothesis Testing is: The z-score at which you would reject the null hypothesis. the mean plus and minus the standard error. The probability of the sample results if the null hypothesis is true. The difference between the mean and the z-score. The z-critical value based on the confidence level desied. When testing...
A biologist is studying the behavior of snails. As a part of this study, the biologist...
A biologist is studying the behavior of snails. As a part of this study, the biologist and his students used snails from a natural population to measure the distances (in cm) that snails travel per day. A sample (m1) of 30 measurements in cm that snails traveled per day is obtained. Generate the sample using the R codes below: set.seed(12345678) Z = rexp(30,0.01) m1 = round(Z,1) State the sample (m1) that you obtained. Use these data to answer the following...
A new kind of typhoid shot is being developed by a medical research team. The old...
A new kind of typhoid shot is being developed by a medical research team. The old typhoid shot was known to protect the population for a mean time of 36 months, with a standard deviation of 3 months. To test the time variability of the new shot, a random sample of 19 people were given the new shot. Regular blood tests showed that the sample standard deviation of protection times was 1.9 months. Using a 0.05 level of significance, test...
A new kind of typhoid shot is being developed by a medical research team. The old...
A new kind of typhoid shot is being developed by a medical research team. The old typhoid shot was known to protect the population for a mean time of 36 months, with a standard deviation of 3 months. To test the time variability of the new shot, a random sample of 23 people were given the new shot. Regular blood tests showed that the sample standard deviation of protection times was 2.1 months. Using a 0.05 level of significance, test...
A new kind of typhoid shot is being developed by a medical research team. The old...
A new kind of typhoid shot is being developed by a medical research team. The old typhoid shot was known to protect the population for a mean time of 36 months, with a standard deviation of 3 months. To test the time variability of the new shot, a random sample of 25 people were given the new shot. Regular blood tests showed that the sample standard deviation of protection times was 1.7 months. Using a 0.05 level of significance, test...
QUESTION 9 9) A researcher is testing the claim that men and women who were arrested...
QUESTION 9 9) A researcher is testing the claim that men and women who were arrested last year have the same number of prior arrests. Data were analyzed and the following SPSS output was given. a) State an Alternative or Research Hypothesis that is being tested with the sample data you have T-Test results for below. b) Are the variances equal for these two groups? c) Report the test statistic value and your decision at a 5% significance level about...
(Q24-Q27) An insurance company has gathered the information regarding the number of accidents reported per day...
(Q24-Q27) An insurance company has gathered the information regarding the number of accidents reported per day over a period of 100 days. The data can be found on the fourth sheet labeled “Accidents” in the “INFO1020 Final Exam DataFile.xlsx”. With the data, you are conducting a goodness-of-fit test to see whether the number of accidents per day can have a Poisson distribution. 24.What is the expected frequency of exactly 2 accidents per day? 25.What is the Chi-square test statistics? Round...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT