Data Science Test focuses on “Graphics Devices”.
1. Every open graphics device is assigned an integer greater than 2.
a) True
b) False
Answer: b
Explanation: Every open graphics device is assigned an integer greater than equal to 2.
2. Point out the correct statement.
a) Vector formats are good for line drawings and plots with solid colors using a modest number of points
b) Vector formats are good for plots with a large number of points, natural scenes or web based plots
c) The default graphics device is always the screen device
d) All of the mentioned
Answer: a
Explanation: Bitmap formats are good for plots with a large number of points, natural scenes or web based plots.
3. Which of the following will copy the plot from one device to another?
a) dev.copy
b) dev.copypdf
c) dev.device
d) all of the mentioned
Answer: a
Explanation: Copying a plot to another device can be useful because some plots require a lot of code and it can be a pain to type all that in again for a different device.
4. Which of the following is used to change active graphic device?
a) dev.set
b) dev.int
c) dev.win
d) all of the mentioned
Answer: a
Explanation: You can change the active graphics device with dev.set() where is the number associated with the graphics device you want to switch to.
5. Point out the wrong statement.
a) File devices are useful for creating plots that can be included in other documents or sent to other people
b) Plots must be created on a graphics device
c) For file devices, there are vector and bitmap formats
d) None of the mentioned
Answer: d
Explanation: For file devices, there are vector and bitmap formats.
6. Which of the following is the second goal of PCA?
a) data compression
b) statistical analysis
c) data dredging
d) all of the mentioned
Answer: a
Explanation: The principal components are equal to the right singular values if you first scale the variables.
7. dev.copy2pdf specifically copy a plot to a PDF file.
a) True
b) False
Answer: a
Explanation: Copying a plot is not an exact operation, so the result may not be identical to the original.
8. Which of the following is a vector file device?
a) png
b) svg
c) bmp
d) none of the mentioned
Answer: b
Explanation: svg stands for scalable vector graphics.
9. Which of the following is alternative technique toprincipal component analysis?
a) Factor analysis
b) Independent components analysis
c) Latent semantic analysis
d) All of the mentioned
Answer: d
Explanation: PC’s may mix real patterns.