bummer

A muffler company advertises that u will receive a rebate if it takes longer than 30min to replace your muffler. Experience has shown that the time taken to replace a muffler is approximately normally distributed with a mean of 25min and a standard deviation of 2.5min. What proportion of customers receive rebates?

The answer is 0.0228.

Then, another follow up question arises,

What should be the rebate-determining time of 30min in previous Q be changed to if the company wishes to provide only 1% of the customers with a rebate?

The answer is 25+2.33(2.5)

I don't understand it at all

there are 500 number of samples. 38 are defective. so the question is, 95% CI for this proportion defective is?

the answer is (0.053, 0.099) but i really want to know how to get there..

I've worked out the standard error for this, and it is 0.012 as sqrt*(pq/n), where p=(38/500)=0.076, q=1-0.076 =0.924

many thanks!

a. 14 σ and 2 π bonds

b. 18 σ bonds

c. 16 σ and 2 π bonds

d. 14 σ and 4 π bonds

the answer is c. can someone please tell me why?

a. 14 σ and 2 π bonds

b. 18 σ bonds

c. 16 σ and 2 π bonds

d. 14 σ and 4 π bonds

the answer is c. can someone tell me why is this so?

Consider a steel guitar string of initial length L=1m and cross-sectional area A=0.5mm^2. The Young's modulus of the steel is Y= 2.0 x10^11 pa. How far (delta L) would such a string stretch under a tension of 1500 ?

Express your answer in millimeters using two significant figures.

i need a step by step guide. the answer is 15mm but i keep getting 66.67mm.

what i did was,

1500/0.5mm^2 = 3000Nmm^-2.

then i convert 2 x10^11 Pa to Nmm^-2 = 200 000Nmm^-2

then, 3000Nmm^2 / 200 000Nmm^-2 = 0.015

using formula, (F/A) / (L/delta L) =Y,

1/0.015 = 66.67mm^2

that's what i got. i know it's wrong, so tell me where did i go wrong please..

Consider a steel guitar string of initial length L=1m and cross-sectional area A=0.5mm^2. The Young's modulus of the steel is Y= 2.0 x10^11 pa. How far (delta L) would such a string stretch under a tension of 1500 ?

Express your answer in millimeters using two significant figures.

i need a step by step guide. the answer is 15mm but i keep getting 66.67mm.

what i did was,

1500/0.5mm^2 = 3000Nmm^-2.

then i convert 2 x10^11 Pa to Nmm^-2 = 200 000Nmm^-2

then, 3000Nmm^2 / 200 000Nmm^-2 = 0.015

using formula, (F/A) / (L/delta L) =Y,

1/0.015 = 66.67mm^2

that's what i got. i know it's wrong, so tell me where did i go wrong please..

Use the following information to answer the questions below. A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 49 percent of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants.

4) What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time?

A) There has been a high rate of mutation of allele A to allele a.

B) The population is undergoing genetic drift.

C) There has been sexual selection favoring allele a.

D) The two phenotypes are about equally adaptive under laboratory conditions.

E) The genotype AA is lethal.

the answer is D. but i still don't understand.

In a hypothetical population of 1,000 people, tests of blood-type genes show that 160 have the genotype AA, 480 have the genotype AB, and 360 have the genotype BB. What is the frequency of the B allele?

A) 0.001

B) 0.002

C) 0.100

D) 0.400

E) 0.600

the answer is E. Can someone please teach me how to do it?

You are studying three populations of birds. Population A has ten birds, of which one is brown (a recessive trait) and nine are red. Population B has 100 birds, of which ten are brown. Population C has 30 birds, and three of them are brown. Which population is most likely to be subject to the bottleneck effect?

A) Population A.

B) Population B.

C) Population C.

D) They are all the same.

E) It is impossible to tell from the information given.

the answer is A. Can someone tell me why?

My rabbit just died almost a week ago.

yeaaaay i'm going to NZ february next year. so...what do u think of the lifestyle in NZ? i'm afraid i couldn't understand the english there lol...

so...do u have any useful info to share about NZ?

i'm going to New Zealand for the 1st time. i don't really know about new zealand, so i really appreciate it if u could tell me more about the weather and what kind of clothing i should wear. is it expensive there?

p/s: i'll be going on 20-something february

Really simple question about MacLaurin series? anyone?

the questions are:

a) obtain the first 4 terms in the MacLaurin Series for e^(-x^2).

b) use the first 2 terms in a) to find an approximation for y= xe^(-x^2) when x is small.

please help me. i don't even understand this topic. at least tell me the what to do.. i don't even learn this thing yet..

the questions are:

a) obtain the first 4 terms in the MacLaurin Series for e^(-x^2).

b) use the first 2 terms in a) to find an approximation for y= xe^(-x^2) when x is small.

please help me. i don't even understand this topic. at least tell me the what to do.. i don't even learn this thing yet..

ok so the equation is y = x℮‾ ˣ², but i can't find its stationary points (max, min points and horizontal inflection points)

i've found the gradient but i got x= -1, and when i checked with the graphical calculator, it's lesser than that. so i've asked my friends and they don't know it either.

find the first 4 terms i the MacLaurin Series for e^-x2

how to solve it? what should we do first?

obtain the first 4 terms in the MacLaurin series for e^-X2

i really have no idea. what should i do first? please help me, i haven't learned this yet and i need to know.

so do you really understand our constitution? i think it's awesome!

is it safe enough to store it in a water bottle? i know it's not safe because the plastic bottle releases dioxin, a chemical that can lead to cancer. so how do you store your drinking water?

is it safe enough to store it in a water bottle? i know it's not safe because the plastic bottle releases dioxin, a chemical that can lead to cancer. so how do you store your drinking water?