INSTRUCTOR: Hello, welcome to AP review for AP Computer Science
Principles.
I'm Mrs. Julie Alano, I teach at Hampton Southeastern High
School in Fishers, Indiana.
Let's get started with some review today.
So question number one.
We're going to take a look at about 10 multiple choice
questions today.
This one is rather lengthy.
You can access all the questions I'm
going to go over today using the PDFs that was on the slide
there on my screen.
Or you can find it in the description on the YouTube
video.
And so you can download that PDF and have
the questions in front of you.
Or you can pause the video if you want to take time
to read the question.
We are going to use this segment of this reading
passage on two questions here.
And there are questions like that on the AP exam
where you have a reading passage and then
you'll have five questions about that one reading passage.
So here's our reading passage.
StreamPal is an audio streaming application for mobile devices
that allows users to listen, to streaming music,
and connect with other users who have similar taste in music.
After downloading the application,
each user creates a username, personal profile,
and contact list of friends who also use the application.
The application uses the device's GPS unit
to track a user's location.
Each time a user listens to a song,
the user can give it a rating from 0 to 5 stars.
The user can access the following features
for each song that the user has rated.
A list of users on the contact list
who have given the song the same rating with links
to those users profiles.
A map showing all the other users
in the area who have given the song the same rating with links
to those users profiles.
A basic stream powered account is free,
but it displays advertisements that
are based on data collected by the application.
For example, if a user listens to a particular artist,
the application may display an advertisement
for concert tickets to the next time the artist comes
to their user city.
Users have the ability to pay a monthly fee for a premium
account which removes the advertisements
from the application.
Which of the following statements
is most likely true about the differences
between the basic version and the premium
version of StreamPal?
So we're looking at the differences between the basic
and the premium.
And a basic StreamPal account is free
but displays advertisements and to pay
the monthly fee for a premium account
in that removes the advertisements.
So there's the key parts of the question
having to do with what we're trying to determine.
All right.
Answer A is more likely to give songs higher ratings.
So users of the basic version are more likely to give songs
higher ratings.
Doesn't seem accurate.
And next one, users of the basic version
are indirectly support StreamPal by allying themselves
to receive advertisements.
That seems accurate, advertisements companies
pay to have those advertisements.
Usually the basic version of StreamPal
spend more on monthly fees.
They're using the basic version, they're
not going to spend money on fees then.
So that doesn't seem accurate.
And users of the basic version of StreamPal
use less data storage space on their devices.
We didn't talk anything about data storage
here on the device, so I don't think that's an answer either.
So it sounds like they're indirectly supporting StreamPal
by allowing themselves to receive advertisements
and StreamPal gets money from those advertisers.
So that's our answer, answer B. All right.
Question 2, again we're looking at the same passage.
This is the exact same passage.
So I'm not going to reread that passage.
Again, if you want to pause and look over it
further you can or you can pull up the PDF.
So our question this time is, which of the following
is most likely to be a data privacy
concern for StreamPal users?
Let's go back to the question here.
The application uses the device's GPS unit
to track a user's location and then
a map of all of their users in the area
who have given the song the same rating shows up.
So answer A, users of the application
are required to write songs in order
to enable all of the application's features.
I don't think that was one of the options, no.
Answer B, users of the application
may have the ability to determine information
about the locations of users that
are not in their contact lists.
So they may have the ability to do that because it shows
all other users in the area who have
given the song the same rating.
So they might have--
that sounds like that's a good answer.
C, users of the application may not
be able to use the application if they
are located in an area with poor internet connection.
Well, that's true.
But we're talking about a data privacy concern
here, so that's not our answer.
Users of the application may not have
similar music taste to any other users or in their contact list.
Again, that could be true but it's not a data privacy
concern.
The data privacy concern is that users of the application
may have the ability to determine information
about the locations of users that are not on their contact
list because it says a map showing all other users who
have given the song the same rating.
So that's our answer, answer B. All right.
Question number 3.
Which of the following is a primary reason
for the use of open protocols on the internet?
Again, open protocols on the internet.
That's how they work.
The protocols are open, everybody
knows the rules, that's how we're all
able to access the internet.
So open protocols allow devices to specify
how data packets are to be routed on the internet advance.
Open protocols ensure that all data transmission
on the internet is kept secure.
Open protocols ensure that all internet
users are provided connections with equal bandwidth.
Or open protocols provide a way to standardize
data transmission between different devices.
Open means there's no security to have to do with it,
so that one's gone.
Open, yes.
But it doesn't specify how the packets
are to be routed in advance.
That's just decided as soon as you send something
on the internet and it doesn't have anything
to do with bandwidth.
So open protocols don't have anything
to do with giving everybody equal bandwidth.
So it is just a way to standardize data transmission
between devices and so that's how
we are all able to use the internet successfully
and easily.
All right.
Question number 4.
The figure below represents a network of physically linked
devices labeled A through F. A line between two devices
indicates a connection.
Devices can communicate only through the connections shown.
Which of the following statements
are true about the ability for devices A and C to communicate.
We are to select two answers.
All right.
We got a lot of animations here, so stick with me.
If devices B and D were to fail, so again,
we were looking for A and C to be able to communicate.
So if B and D failed, so if those are gone,
then information sent from device A
could not reach device C. So let's take a look here.
Is there any way for A to get to C right now?
Nope, because A goes to B, A goes to D,
and that's the only way to go any further from A. So
therefore, again, which of the following statements are true?
So if B and D were to fail, then information sent from A
could not reach device C, so that is true.
All right.
Now we're looking at B and F. So I got B marked out still and F,
so those two failed.
So then information from A could not reach C.
Oh, but now we can go to D and there's that line all
the way from D around to C. So it
looks like I can still get there, A to D
and then all the way around to C,
so that one is not an answer.
Now if D and F failed, so I got D and F marked out now,
then information sent from A could not reach C. So again,
we're looking, is there a way to get from A to C?
So A can go to B but then it can't go any further
or it could go to E.
So we go A to B to E but it doesn't
look like there's any way for me to get to C,
so that one seems true.
And/or final one, if E and F were to fail,
then information sent from A could not reach C. Nope,
we still get that D this time.
So again, if A can get to D, then it
can go all the way around to see on that one wire there.
And so that one is not true and so our two answers are A and D.
All right.
Question number 5.
A computer has two processors that
are able to run in parallel.
The table to the right indicates the amount of time
it takes either processor to execute
four different processes.
Assume that none of the processes
is dependent on any of the other processes.
A program is used to assign processes
to each of the processors.
Which of the following describes how
the program should assign the four processes to optimize
execution time?
So the amount of time it takes either process to execute.
So the table shows how much it takes.
All right.
So the program should assign the four processes
to optimize execution.
So basically we just want to add up.
So if we assign W and X, that would be 50 seconds
and Y and Z would be 105.
So you would have to use the higher number there, 105.
Answer B, Y and W would be 65 seconds,
X and Z would be 90 seconds, so that one's 90.
W and Z would be 80 seconds, X and Y would be 75,
so that one will only take 80 seconds.
And the last one, Z, which is 60 and then we
add up all three others, that would be 95.
So again, we're looking for the one which has the--
you're looking at the highest number for each one
and which one of those highest numbers is the smallest.
So it was 105, it was 90, it was 80, it was 95.
So therefore, C with 80 as the highest number,
that is our answer.
All right.
Next question.
Which of the following best explains
how fault tolerance in a network is achieved?
Again, we're talking about the term fault tolerance.
So let's take a look by providing high bandwidth
connections between devices enabling
data packets to be transmitted as quickly as possible.
So high bandwidth connections, does that
have to do with fault tolerance?
Or by providing multiple paths between devices,
enabling routing to occur and even in the presence
of a failed component.
Or by providing open network protocols
ensuring that all devices on the network
are interacting in a standard way.
Or our last option, by providing software
to monitor all network traffic ensuring that data packets
are sent and received in the proper order.
Again we're talking about fault tolerance,
we want to be able to have that internet app all the time.
So in routing our things whenever
needed even if something fails like we saw earlier
and so that is answer choice B.
So that is the correct answer for fault tolerance.
All right.
Which of the following actions is
most likely to be effective in reducing the digital divide
at a local level?
The digital divide in access to the internet.
We've talked about it here a lot,
having access to the internet is very helpful.
But right now, some people may not have access
and may not have access to high speed internet,
and we're also talking about having access to devices.
So we're trying to reduce that at a local level.
So first option, creating an application that
offers coupons and discounts for local businesses.
Doesn't seem accurate.
B, offering a discount to utility customers
who pay their bills online instead of by mail.
That seems to favor people who have access
to pay their bills online.
C, providing free community access
to computers at schools, libraries, and community
centers.
So add more access for the community.
Or D, requiring applicants for local government jobs
to complete an online application.
Again, we're limiting people who don't have online resources.
So to help reduce the digital divide,
we should do C, provide free community access
to computers at schools, libraries, and community
centers.
A mobile application is used to display local traffic
conditions, which of the following features
of the application best exemplifies
the use of crowdsourcing?
So crowdsourcing is where a bunch of people
provide information.
So is it A?
Users can save an address to be used at a later time.
Or is it B?
Users can turn on alerts to be notified
about traffic accidents.
C, users can submit updates on local traffic conditions
in real time.
Or D, users can use the application
to avoid heavenly congested areas.
Well, you can't do that if you don't know where those are
and so that's why we need to crowdsource
those updates in real time so that we
can avoid those congestions.
So the answer is C, how can crowdsourcing help us out?
All right.
A programmer created a piece of software
and wants to publish it using a Creative Commons license, which
of the following is a direct benefit of publishing
the software with this type of license?
Again, a Creative Commons license.
Is it A?
The programmer can ensure the algorithms used in the software
are free from bias.
Is it B?
The programmer can ensure that the source
code for the software is backed up for archival purposes.
Is it C?
The programmer can include code that
was written by other people in the software
without needing to obtain permission.
Or is it D?
The programmer can specify the ways
that other people are legally allowed to use and distribute
the software.
We're talking about a license and that's Creative Commons
license and publishing and sharing it.
So there's our answer to that final one,
how you want to use and distribute it
so you can specify that with a Creative Commons license,
so our answer is D.
A city's police department has installed cameras
throughout the city streets.
The cameras capture and store license plate data
from cars driven and parked throughout the city.
The authorities use recorded license plate data
to identify stolen cars and to enforce parking regulations.
Which of the following best describes
a privacy risk that could occur if this method of data
collection is misused?
So remember the cameras capture and store license
plate data and the authorities use
that data to identify stolen cars
and to enforce parking regulations.
So which best describes the privacy risk
if the data collection is misused?
Answer A, the cameras may not be able to read license plates
in poor weather conditions.
That doesn't seem like a privacy risk.
Local business owners could lose customers
who are unwilling to park in the city.
Again, we're looking for a privacy risk.
Or C, traffic personnel who work for the city could
lose their jobs if their services are no longer needed.
Again, we're talking about a privacy risk, that
doesn't seem like a risk to me.
Or D, the vehicle location data could
be used to monitor the movements of city residents.
That seems like the correct answer
as I've highlighted their.
Right, that's a privacy risk.
They could see where you're going
and that could be an issue.
So answer there is D All right.
Our final question.
Which of the following best exemplifies the use
of multifactor authentication?
A computing device enables users to input information
using multiple interfaces, including a keyboard, a mouse
or a touchpad.
So that's our first option, A. Option B,
a user employs a public key encryption method
that uses one key to encrypt information in a different key
to decrypt information.
Or is multifactor authentication, C,
a website requires a user to enter a password
as well as a numeric code received via text message
before the user can log into an account.
Or is it D?
Multiple users share an account to a web based software program
and each user has an individual username and password.
So multifactor authentication, we're talking about passwords
and being able to log in, so our answer here is C. So
correct answer, C. All right.
That is it for today.
Here are the topics we've covered.
We've covered the internet, fault tolerance, parallel
and distributed computing, as well as the digital divide,
crowdsourcing, legal and ethical concerns, and safe computing.
If you want to review these further,
you can find AP data videos on these topics on AP Classroom.
Thank you for joining me today.
See you next time.