# Question: An auditor for the U S Postal Service wants to examine

An auditor for the U.S. Postal Service wants to examine its special two-day priority mail handling to determine the proportion of parcels that actually arrive within the promised two-day period. A randomly selected sample of 1600 such parcels is found to contain 1250 that were delivered on time. Does the sample data provide evidence to conclude that the percentage of on-time parcels is more than 75% (using ( = .01)? Use the hypothesis testing procedure outlined below.

a. Formulate the null and alternative hypotheses.

b. State the level of significance.

c. Find the critical value (or values), and clearly show the rejection and non rejection regions

d. Compute the test statistic.

e. Decide whether you can reject Ho and accept Ha or not.

f. Explain and interpret your conclusion in part e. What does this mean?

g. Find the observed p-value for the hypothesis test and interpret this value. What does this mean?

h. Does this sample data provide evidence (with ((= .01), that the percentage of on-time parcels is more than 75%?

a. Formulate the null and alternative hypotheses.

b. State the level of significance.

c. Find the critical value (or values), and clearly show the rejection and non rejection regions

d. Compute the test statistic.

e. Decide whether you can reject Ho and accept Ha or not.

f. Explain and interpret your conclusion in part e. What does this mean?

g. Find the observed p-value for the hypothesis test and interpret this value. What does this mean?

h. Does this sample data provide evidence (with ((= .01), that the percentage of on-time parcels is more than 75%?

## Answer to relevant Questions

A sample of n=20 has a mean of M=40. If the standard deviation is s=5, would a score of x=55 be considered an extreme value? Why or why not?Researchers wanted to explore self-esteem in adolescent boys and adolescent girls. They used a 5-point Likert-type self-esteem inventory; a 1 = strongly disagree and 5 = strongly agree. Their results yielded the following t ...An Ad week Media/Harris Poll revealed that 44% of U.S. adults in the 18–34 years category think that “Made in America” ads boost sales. A different Harris Interactive poll showed that 78% of U.S. adults in the 18–34 ...You have been asked to assess the bond bellow:Bond Details Par Value €100 Coupon Coupon (1): €8 (2012-2017) Coupon (2): €10 (2018-∞) Yield 7.5% (2012-2015) 9.2% (2016-2019) You are required to address the following ...Western Pipeline, Inc., has been very successful in the last five years. Its $1,000 par value convertible bonds have a conversion ratio of 28. The bonds have a quoted interest rate of 5 percent a year. The firm’s common ...Post your question