Are births really evenly distributed across the days of aweek? Here are data on 700 births in a hospital:
Day
Sun.
Mon.
Tue.
Wed.
Thu.
Fri.
Sat.
Observed births
89
110
116
104
94
106
81
Null hypothesis: the births are evenly distributed across thedays of the week
Research hypothesis: the births are not equally probable onall days of the week?
Choose α = 5%
Test statistic used: χ2 =
Decision : Reject Ho if χ2 is too big.
Calculations and Conclusion
1Ëš Arrange the data in the form of a frequency distribution(See the table above).
2Ëš Obtain the expected frequency for each day.
Day
Sun.
Mon.
Tue.
Wed.
Thu.
Fri.
Sat.
Expected births
3Ëš Setup a summary table to calculate the Chi-squarevalue.
4Ëš Find the degree of freedom.
5˚ Compare the calculated Chi-square value with theappropriate value from the χ2 Table.
The calculated χ2 value is
A) 7.15
B) 8.27
C) 9.26
D) 10.10
E) 11.92
F) 12.76
G) 13.68
H) 16.42
I) 19.12
J) 23.86.
