A CI is desired for the true average stray-load loss (watts) for a certain type

Question

A CI is desired for the true average stray-load loss (watts) for a certain type of induction motor when the line current is held at 10 amps for a speed of 1500 rpm. Assume that stray-load loss is normally distributed with = 3.3. (Round your answers to two decimal places.)

(a) Compute a 95% CI for when n = 25 and x = 51.7. , watts

(b) Compute a 95% CI for when n = 100 and x = 51.7. , watts (

c) Compute a 99% CI for when n = 100 and x = 51.7. , watts

(d) Compute an 82% CI for when n = 100 and x = 51.7. , watts

(e) How large must n be if the width of the 99% interval for is to be 1.0? (Round your answer up to the nearest whole number.) n =

Explanation / Answer

Part-a

95% CI = 51.7±1.96*3.3/sqrt(25)=( 50.4064           52.9936)

Part-b

95% CI = 51.7±1.96*3.3/sqrt(100)=( 51.0532         52.3468)

Part-c

99% CI = 51.7±2.58*3.3/sqrt(100)=( 50.8486         52.5514 )

Part-d

82% CI = 51.7±1.34 *3.3/sqrt(100)=( 51.2578        52.1422)

Part-e

Width =1

So margin of error E =1/2=0.5

So, sample size n>= (z*/E)2=(2.58*3.3/0.5)2=289.952784

So sample size n=290

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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