Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

For the binomial distribution with the given values for n and p, state whether o

ID: 3207786 • Letter: F

Question

For the binomial distribution with the given values for n and p, state whether or not it is suitable to use the normal distribution as an approximation. n = 31 and p = .9

Normal approximation is not suitable.

Normal approximation is suitable.

.2946

.3229

.1871

.4936

Normal approximation is not suitable.

Normal approximation is suitable

.2852

.7852

.2148

.7611

0.9318

0.0424

0.1739

0.7248

0.0934

0.0823

0.0869

0.9066

Normal approximation is not suitable.

Normal approximation is suitable.

Use the normal distribution to approximate the desired probability. Find the probability of getting at most 30 fives in 200 tosses of a fair 6-sided die.

.2946

.3229

.1871

.4936

For the binomial distribution with the given values for n and p, state whether or not it is suitable to use the normal distribution as an approximation. n = 54 and p = .7

Normal approximation is not suitable.

Normal approximation is suitable

A library determines that its books are returned on time 90% of the time. If 450 books are checked out, what is the probability that more than 400 will be returned on time?

.2852

.7852

.2148

.7611

Assume that women's heights are normally distributed with a mean of 63.6 inches and a standard deviation of 2.5 inches. If 90 women are randomly selected, find the probability that they have a mean height between 62.9 inches and 64.0 inches.

0.9318

0.0424

0.1739

0.7248

Two percent of CD-ROM drives produced in a certain plant are defective. Estimate the probability that of 10,000 randomly selected drives, at least 219 are defective.

0.0934

0.0823

0.0869

0.9066

Explanation / Answer

here n(1-p) =31*0.1=3.1 which is less then 5; hence not suitable

for die : probability of gettting a five =1/6

hence mean =np=200/6 =33.33

and std deviation =(np(1-p))1/2 =5.27

hence probabilty of gettting at most 30 five, out of 200 =P(X<=30)=P(Z<(30.5-33.33)/5.27)=P(Z<-0.53)=0.2852

For the binomial distribution with the given values for n and p, state whether or not it is suitable to use the normal distribution as an approximation. n = 54 and p = .7

normal approximation is suitable as np>5 and n(1-p)>5

3) mean =63.6 and std deviation =2.5

hence std error of mean =2.5/(90)1/2=0.2635

P(62.9<X<64)=P((62.9-63.6)/0.2635<Z<(64-63.6)/0.2635)=P(-2.6563<Z<1.5179)=0.9355-0.0040=0.9315

hence option 0.9318 is right

4) p=0.02

mean =np=1000=0.02*10000=200

std deviation =(np(1-p))1/2 =14

hence P(X>219)=1-P(X<219)=1-P(Z<(218.5-200)/14)=1-P(Z<(1.3214)=1-0.9068=0.0931

option 0.0934 is correct.