A manufacturer claims that the life span of its tires is 48 comma 000 miles. You

Question

A manufacturer claims that the life span of its tires is 48 comma 000 miles. You work for a consumer protection agency and you are testing these tires. Assume the life spans of the tires are normally distributed. You select 100 tires at random and test them. The mean life span is 47 comma 849 miles. Assume sigmaequals800. Complete parts (a) through (c). (a) Assuming the manufacturer's claim is correct, what is the probability that the mean of the sample is 47 comma 849 miles or less? nothing (Round to four decimal places as needed.) (b) Using your answer from part (a), what do you think of the manufacturer's claim? The claim is inaccurate accurate because the sample mean would not would be considered unusual since it does not lie lies within the range of a usual event, namely within 1 standard deviation 2 standard deviations 3 standard deviations of the mean of the sample means. (c) Assuming the manufacturer's claim is true, would it be unusual to have an individual tire with a life span of 47 comma 849 miles? Why or why not? Yes No , because 47 comma 849 does not lie lies within the range of a usual event, namel

Explanation / Answer

probability that the mean of the sample is 47,849 miles or less

b)

  The claim is  accurate because the sample mean would not   considered unusual since it  lies within the range of a usual event namely within  2 standard deviations  of the mean of the sample means.

c) No  because 47,849 lies within the range of a usual event

for normal distribution z score =(X-)/ here mean=       = 48000.000 std deviation   == 800.00 sample size       =n= 100 std error=x=/n= 80.0000

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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