In: Statistics and Probability
The safety director of a large steel mill took samples at random from company records of minor work-related accidents and classified them according to the time the accident took place.
Number of | Number of | |||||||
Time | Accidents | Time | Accidents | |||||
8 up to 9 a.m. | 10 | 1 up to 2 p.m. | 9 | |||||
9 up to 10 a.m. | 19 | 2 up to 3 p.m. | 20 | |||||
10 up to 11 a.m. | 9 | 3 up to 4 p.m. | 6 | |||||
11 up to 12 p.m. | 8 | 4 up to 5 p.m. | 7 | |||||
Click here for the Excel Data File
Using the goodness-of-fit test and the 0.01 level of significance, determine whether the accidents are evenly distributed throughout the day.
H0: The accidents are evenly distributed
throughout the day.
H1: The accidents are not evenly distributed
throughout the day.
State the decision rule, using the 0.01 significance level. (Round your answer to 3 decimal places.)
Compute the value of chi-square. (Round your answer to 3 decimal places.)
What is your decision regarding H0?
H0: The accidents are evenly distributed
throughout the day.
H1: The accidents are not evenly distributed
throughout the day.
observed frequencey, O | expected proportion | expected frequency,E | (O-E)²/E | ||
10 | 0.125 | 11.00 | 0.091 | ||
19 | 0.125 | 11.00 | 5.818 | ||
9 | 0.125 | 11.00 | 0.364 | ||
8 | 0.125 | 11.00 | 0.818 | ||
9 | 0.125 | 11.00 | 0.364 | ||
20 | 0.125 | 11.00 | 7.364 | ||
6 | 0.125 | 11 | 2.273 | ||
7 | 0.125 | 11 | 1.455 |
chi square test statistic,X² = Σ(O-E)²/E =
18.545
level of significance, α= 0.01
Degree of freedom=k-1= 8 -
1 = 7
P value = 0.0097 [ excel function:
=chisq.dist.rt(test-stat,df) ]
Decision: P value < α, Reject Ho
............
THANKS
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