# 2.2 Exam 3: chapters 5, 6, & 7

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Practice final exam for use with Collaborative Statistics (col10522) by Barbara Illowsky and Susan Dean.

## Questions 1 – 3 refer to the following:

Assume the amount of money seventh–grade students spend on food each day at school is exponentially distributed with an average of \$2.50.

Which graph best describes the distribution?

• ## D

B

Find the probability that a randomly selected seventh–grade student spends less than \$4 a day on food.

0.7981

0.2019

0.9999
• ## D

0.0001

A

85% of the seventh–grade students spend more than what amount per day?

\$2.12

\$0.75

\$4.74

\$0.41

D

## Questions 4 – 5 refer to the following:

The amount of time that intermediate algebra students at Leland High School spend doing their homework per day is normally distributed with a mean 1.5 hours and standard deviation 0.75 hours.

If one student is randomly chosen, what is the probability that the student does intermediate algebra homework at least 2 hours per day?

0.7475

0.4259

0.2525
• ## D

0.6784

C

60% of these students spend at most how many hours doing their homework?

1.69 hours

1.31 hours

1.5 hours

0.2533 hours

A

## Questions 6 – 7 refer to the following:

Llamas are excellent pack animals. It is known that the weight of supplies carried by llamas follows a normal distribution with a mean of 62.5 pounds and a standard deviation of 6 pounds.

Find the probability that the weight of supplies carried by one randomly chosen llama is between 60 and 70 pounds.

0.4441

0.5559

0.8944
• ## D

1

B

The middle 50% of weights of supplies carried by a randomly chosen llama is between _____ and _____.

• ## A

0 and 62.5 pounds
• ## B

58.45 and 66.55 pounds
• ## C

56.5 and 68.5 pounds
• ## D

There is not enough information given.

B

Which of the following are true for the normal distribution?

• ## I

More values fall close to the mean than fall far away from the mean.
• ## Ii

The mean and standard deviation cannot be the same.
• ## Iii

A change in µ causes the graph to shift to the left or right and changes the shape of the graph.
• ## Iv

A change in s causes a change in the shape of the normal curve.

I, IV
• ## B

I, II, III, IV

I, II, III

III, IV

A

## Questions 9 – 13 refer to the following:

The length of time junior high school students sleep per night follows an approximate uniform distribution from seven to eleven hours. Suppose we randomly select a junior high student.

Find the probability that the randomly selected student sleeps less than 8 1/2 hours per night.

.2143

0.7727

0.4705
• ## D

0.375

D

Find the probability that the randomly selected student sleeps eight to twelve hours per night.

0

1

0.75
• ## D

0.25

C

On average, how long does a junior high school student sleep per night?

.2143

0.7727

0.4705
• ## D

0.375

B

On average, how long does a junior high school student sleep per night?

9.6 hours

6.5 hours

7.8 hours
• ## D

8.4 hours

D

We are interested in the probability that a randomly selected student sleeps less than eight hours, knowing that he/she sleeps less than ten. Which graph best depicts this situation?

• ## D

C

#### Questions & Answers

can someone help me with some logarithmic and exponential equations.
sure. what is your question?
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
a perfect square v²+2v+_
kkk nice
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
rolling four fair dice and getting an even number an all four dice
Kristine 2*2*2=8
Differences Between Laspeyres and Paasche Indices
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
is it 3×y ?
J, combine like terms 7x-4y
im not good at math so would this help me
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
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