The Ping Company makes custom-built golf clubs and competes in the $4 billion go

Question

The Ping Company makes custom-built golf clubs and competes in the $4 billion golf equipment industry. To improve its business processes Ping decided to seek ISO 9001 certification. s part of this process, a study of the time it took to repair golf club sent to the company by mail determined that 10% of orders were sent back to the customers in 5 days or less. Ping examined the processing of repair orders and made changes. Following the changes, 88% of orders were completed within 5 days. Assume that each of the estimated percents is based on a random sample of 200 orders. How many orders were completed in 5 days or less before the changes? orders Give a 90% confidence interval for the proportion of orders completed in this time. (Round your answers to three decimal places.) How many orders were completed in 5 days or less after the changes? Orders Give a 90% confidence interval for the proportion of orders completed in this time. (Round your answers to three decimal places.) Give a 90% confidence interval for the improvement. Express this both for a difference in proportions and for a difference in percents. (Define the groups so that the difference will be positive. Round your answers for proportions to three decimal places.) proportions percents

Explanation / Answer

a) number of orders completed in 5 days or less before changes =np=200*0.1=20

here p=0.1 ; n=200

std error =(p(1-p)/n)1/2 =0.0212

for 90% CI, z=1.645

hence 90% confidence interval =p -/+z*std error =0.065 ; 0.135

b)number of orders completed in 5 days or less after changes =np=200*0.88=176

std error =(p(1-p)/n)1/2 =0.023

for 90% CI, z=1.645

hence 90% confidence interval =p -/+z*std error =0.842 ; 0.918

c)

here p1=0.88 ; p2=0.1 ; n1=n2=200

hence std error =(p1(1-p1)/n1+p2(1-p2)/n2)1/2 =0.0313
therefore proportion =p1-p2 -/+ z*std error =0.729 ; 0.831

percents =72.9% ; 83.1%

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.