i safari File Edit View History Bookmarks Window Help 52% H. Wed 4:24 PM a Guide

Question

i safari File Edit View History Bookmarks Window Help 52% H. Wed 4:24 PM a Guided Solutions and Study Help | Chegg.com Connect Chapter 8 Saved Help Save & Exit Submit 41 PM Check my work 4 A normal population has a mean of 65 and a standard deviation of 13. You select a random sample of 25. een Shot 12..17.44 PM Compute the probability that the sample mean is: (Round your z values to 2 decimal places and final answers to 4 decimal places) points a. Greater than 69. een Shot 12...20.32 PM eBook abili Print een Shot 12...0.38 PM b. Less than 61. cen Shot 2...22.25 PM een Shot 2...22.27 PM c. Between 61 and 69 6

Explanation / Answer

Mean is 65 and s is 13

for sample size 25, the standard error is SE=s/sqrt(N)=13/sqrt(25)=13/5=2.6

z is (xbar-mean)/SE

a) P(xbar>69)=P(z>(69-65)/2.6)=P(z>1.54) or 1-P(z<1.54), from normal table is 1-0.9382=0.0618

b) P(xbar<61)=P(z<(61-65)/2.6)=P(z<-1.54) or 1-P(z<1.54) or 0.0618

c) P(61<xbar<69)=P(xbar<69)-P(xbar<61)=0.9382-0.0618=0.8764

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

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