The mean speed of a sample of vehicles along a stretch of highway is 67 miles pe

Question

The mean speed of a sample of vehicles along a stretch of highway is 67 miles per hour, with a standard deviation of 4 miles per hour. Estimate the percent of vehicles whose speeds are between 63 miles per hour and 71 miles per hour. Then estimate the number of vehicles whose speeds are between 63 miles per hour and 71 miles per hour. The mean speed of a sample of vehicles along a stretch of highway is 67 miles per hour, with a standard deviation of 4 miles per hour. Estimate the percent of vehicles whose speeds are between 63 miles per hour and 71 miles per hour. Then estimate the number of vehicles whose speeds are between 63 miles per hour and 71 miles per hour.

Explanation / Answer

Compute z1=(x-)/

=(63-67)/4=-1

Z2=(71-67)/4=1

Thus, the required probability P(63<x<67)

=P(z1<1)-P(z2<-1)

=0.8413-0.1587

=0.6826

The required percentage is 68.26%

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

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