Question

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 11.29 with a standard deviation of 3.00 pages.

    

(a-1)

Find the test statistic. (Round your answer to 4 decimal places.)

  

The test statistic

  

(a-2)	At the .01 level of significance, is the true mean greater than 10?
	Yes No

  

(b)	Use Excel to find the right-tail p-value. (Round your answer to 4 decimal places.)

  

p-value

Answer 1

n=35, =10, = 11.29, s= 3.00 , =0.01

Ho: 10

Ha: 10

(a-1)  Find the test statistic

t = 2.5439

The test statistic = 2.5439

Calculate the critical value for the right test with df= n-1 = 35-1 =34

using t table we get

critical value = 2.441

(a-2) Decision rule

if test statistics > critical value then Reject Ho.

here,  (test statistics = 2.5439) > (critical value = 2.441)

hence, Reject Ho.

Yes, At the 0.01 level of significance, the true mean is greater than 10

b) We are using Excel to find the right-tail p-value.

Command for right-tail p-value is

=TDIST(2.5439,34,1)

we get P-Value = 0.007838

P-Value = 0.0078

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