RES 342 E-TEXT WEEK 2 (9.54,9.56,9.62,9.64) EXCELLENT TUTORIAL

 

9.54 Faced with rising fax costs, a firm issued a
guideline that transmissions of 10 pages or more should be sent by 2-day mail
instead. Exceptions are allowed, but they want the average to be 10 or below.
The firm examined 35 randomly chosen fax transmissions during the next year,
yielding a sample mean of 14.44 with a standard deviation of 4.45 pages.

 

(a)
At the .01 level of significance, is the true mean greater than 10?

 

(b)
Use Excel to find the right-tail p -value.

 

9.56
A coin was
flipped 60 times and came up heads 38 times.

 

(a) At the .10 level of significance, is the
coin biased toward heads? Show your decision rule and calculations.

 

(b) Calculate a p -value and interpret
it.

 

9.62
The Web-based
company ‘ Oh Baby! Gifts’ has a goal of processing 95 percent of its
orders on the same day they are received. If 485 out of the next 500 orders are
processed on the same day, would this prove that they are exceeding their goal,
using α = .025?

 

9.64
an auditor
reviewed 25 oral surgery insurance claims from a particular surgical office,
determining that the mean out-of-pocket patient billing above the reimbursed
amount was $275.66 with a standard deviation of $78.11.

 

(a) At the 5 percent level of significance,
does this sample prove a violation of the guideline that the average patient
should pay no more than $250 out-of-pocket?

 

State your hypotheses and decision rule.

 

(b) Is this a close decision?