A service company recently revised its call-routing procedures in an attempt to increase
efficiency in routing customer calls to the appropriate agents. A random sample of customer
calls was taken before the revision, and another random sample of customer calls was taken
after the revision. The selected customers were asked if they were satisfied with the service call
The difference in the proportions of customers who indicated they were satisfied
Pour - Pecore) was calculated. A 90 percent confidence interval for the difference is given as
-0.02,0.11). The manager of the company claims that the revision in procedure will change
the proportion of customers who will indicate satisfaction with their calls.
Does the confidence interval support the manager's claim?
No. The value of Ois contained in the interval, which indicates that it is plausible
that there is no difference in the proportion of customers who will indicate
satisfaction with their calls.
No. All values in the interval are less than 0.12, which indicates that the
difference in the proportion of customers who will indicate satisfaction with
their calls is very small
Yes. There are more positive values in the interval than negative values, which
indicates that more customers indicated satisfaction with their calls after the
revision
Yes. The length of the interval is greater than 0.10, which indicates that the
sample difference in the proportion of customers who will indicate satisfaction
with their calls is plausible.
i

(A) No. The value of 0 is contained in the interval, which indicates that it is plausible that there is no difference in the proportion of customers who will indicate satisfaction with their calls.

Step-by-step explanation:

According to CollegeBoard.org,

"The confidence interval does not support the claim of a difference. When pafter=pbefore, the difference pafter−pbefore=0. A value of 0 contained in a confidence interval for a difference indicates that 0 is a plausible value for that difference. It is plausible that the proportion of satisfied customers after the revision is the same as that before the revision."