ANOVA test performed determined that not all mean commute ti

ANOVA test performed determined that not all mean commute times across the four cities are equal. However, it did not indicate which means differed. To find out which population means differ requires further analysis of the direction and the statistical significance of the difference between paired population means. Fisher 95% confidence intervals are shown below.

How many pairs of cities show a significant difference in average commute times to work?

teacher\'s answer is 4 but i dont see how he found that. please help

Lower Upper Houston - Charlotte Fisher\'s 95% confidence intervals 17.9257.08 FishersHouston - Tucson 29.75 68.91 Houston - Akron43.75 82.91 Charlotte - Tucson7.75 31.41 Charlotte - Akon6.25 45.41 -5.58 33.58 arlotte Akron Tucson - Akron

Solution

charlotte tucson and tucson akron has no much significant differene according the interval

while all rest 4 have a much significant difference

as in houston charlotte lower is 17.92 while in charlotte akron the lower is 6.25

which is a difference of more then 10 and there upper limit difference is more than 12

similarly there is a huge difference between houston-tucson and houston akron

hence the answer will be 4