In: Statistics and Probability
The national distribution of fatal work injuries in a country is shown in the table to the right under National %. You believe that the distribution of fatal work injuries is different in the western part of the country and randomly select 6231 fatal work injuries occurring in that region. At alpha equals 0.05 can you conclude that the distribution of fatal work injuries in the west is different from the national distribution? Complete parts a through d below. Cause National % Western Frequency Transportation 43% 2893 Equipment 19% 1162 Assaults 15% 805 Falls 13% 749 Harmful fumes 7% 531 Fires 3% 91
a. State Upper H 0 and Upper H Subscript a and identify the claim. What is the null hypothesis, Upper H 0? A. The distribution of fatal work injuries in the west differs from the expected distribution. B. The distribution of fatal work injuries in the west is 43% transportation, 19% equipment, 15 % assaults, 13% falls, 7% harmful fumes, and 3% fires. C. The distribution of fatal work injuries in the west is 2893 transportation, 1162 equipment, 805 assaults, 749 falls, 531 harmful fumes, and 91 fires. What is the alternate hypothesis, Upper H Subscript a? A. The distribution of fatal work injuries in the west is the same as the expected distribution. B. The distribution of fatal work injuries in the west is 43% transportation, 19% equipment, 15 % assaults, 13% falls, 7% harmful fumes, and 3% fires. C. The distribution of fatal work injuries in the west differs from the expected distribution.
Which hypothesis is the claim? Upper H 0 Upper H Subscript a
b. Determine the critical value, font size increased by 1 font size increased by 1 font size increased by 1 chi Subscript 0 Superscript 2, and the rejection region. font size increased by 1 font size increased by 1 font size increased by 1 chi Subscript 0 Superscript 2equals nothing (Round to three decimal places as needed.)
Determine the rejection region. A. font size increased by 1 font size increased by 1 font size increased by 1 chi squared greater than font size increased by 1 font size increased by 1 font size increased by 1 chi Subscript 0 Superscript 2 B. font size increased by 1 font size increased by 1 font size increased by 1 chi squared less than or equals font size increased by 1 font size increased by 1 font size increased by 1 chi Subscript 0 Superscript 2 C. font size increased by 1 font size increased by 1 font size increased by 1 chi squared greater than or equals font size increased by 1 font size increased by 1 font size increased by 1 chi Subscript 0 Superscript 2 D. font size increased by 1 font size increased by 1 font size increased by 1 chi squared less than font size increased by 1 font size increased by 1 font size increased by 1 chi Subscript 0 Superscript 2
c. Calculate the test statistic. font size increased by 1 font size increased by 1 font size increased by 1 chi squaredequals nothing (Round to three decimal places as needed.)
(d) Decide whether to reject or fail to reject the null hypothesis. Then interpret the decision in the context of the original claim. Reject Reject Fail to reject Upper H 0. At the 5% significance level, there is is is not enough evidence to conclude that the western distribution of fatal work injuries differs from differs from is the same as the national distribution.
Solution:-
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
Null hypothesis: B) The distribution of fatal work
injuries in the west is 43% transportation, 19% equipment, 15 %
assaults, 13% falls, 7% harmful fumes, and 3% fires.
Alternative hypothesis: C) The distribution of fatal work injuries
in the west differs from the expected distribution.
Formulate an analysis plan. For this analysis, the significance level is 0.05. Using sample data, we will conduct a chi-square goodness of fit test of the null hypothesis.
Analyze sample data. Applying the chi-square goodness of fit test to sample data, we compute the degrees of freedom, the expected frequency counts, and the chi-square test statistic. Based on the chi-square statistic and the degrees of freedom, we determine the P-value.
DF = k - 1 = 6 - 1
D.F = 5
(Ei) = n * pi
X2 = 109.87
X2Critical = 11.07
Rejection region is X2 > 11.07
where DF is the degrees of freedom, k is the number of levels of the categorical variable, n is the number of observations in the sample, Ei is the expected frequency count for level i, Oi is the observed frequency count for level i, and X2 is the chi-square test statistic.
Interpret results. Since the X2-value lies in the rejection region, hence we have to reject the null hypothesis.
Reject H0. At the 5% significance level, there is is enough evidence to conclude that the western distribution of fatal work injuries differs from the national distribution.