Hasan O.

asked • 03/24/16

why the average of the two 95% confidence interval limits for lower and upper speeds not equal to average speed based on average running time ?

for example : Given the normal distribution of running times, the
mean running time for the section (3mi) is 196 seconds, and 95% of
all running times would fall within 1.96(15) = 29.4 seconds of
this value. Thus the 95% interval for travel times would be
between 196 - 29.4 = 166.6 seconds and 196 + 29.4 = 225.4
seconds. The speeds corresponding to these running times
(including the average) are:
S 1 = (3mi/225.4s)*(3600s/h) = 47.9 mi/hr
S av =(3mi/196s)*(3600s/h) = 55.1 mi/hr
S 2 = (3mi/166.6s)*(3600s/h) = 64.8 mi/hr

S1 + S2 not equal to =55.1 why?

1 Expert Answer


Arnold F. answered • 03/24/16

5 (53)

College Professor & Expert Tutor In Statistics and Calculus

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