Let's get practical (Stats, R and Study Design)

Question 1

Calculate the median for the following numbers:

23, 56, 87, 30, 28, 45, 66, 18, 49, 48

Answer 1

Step 1: Sorting
18, 23, 28, 30, 45, 48, 49, 56, 66, 87

Step 2: Calculating
(45 + 48) / 2 = 46,5

Question 2

Calculate the median for the following numbers:

23, 56, 87, 30, 28, 45, 66, 18, 49, 48, 55

Answer 2

Step 1: Sorting
18, 23, 28, 30, 45, 48, 49, 55, 56, 66, 87

Step 2: Pick the middle (odd numbers)
48

Question 3

Calculate the mean:

4, 2, 3, 1, 1, 5, 4, 4

Answer 3

( 4 + 2 + 3 + 1 + 1 + 5 + 4 + 4) / 8 = 3

Question 4

Calculate the median for the folowing numbers:

4, 2, 3, 1, 1, 5, 4, 4

Answer 4

Step 1: Sorting
1, 1, 2, 3, 4, 4, 4, 5

Step 2: Calculating
(3 + 4) / 2 = 3,5

Question 5

What is the mode from this numbers?

5,2,1,2,6

Answer 5

Mode = 2

Question 6

What is the mode for the following data set?

5, 6, 7, 7, 9, 5, 7, 5, 10, 7, 12, 5

Answer 6

Mode1 = 5
Mode2 = 7

Question 7

Calculation with R

You have the variable x and want to assign the integer “5” to it. How can we do that?

Answer 7

x <- 5

Question 8

Calculation with R

You want to assign an vector with x=1, y=2 and z=3 in the variable myVector. How do that work?

Answer 8

myvector <- c(1,2,3)

Question 9

Calculation with R

What is the output of the following function:

seq(1,5,1)

Answer 9

1 2 3 4 5

Question 10

Calculation with R

What is the output of the following code:

variable <- c(10,10,11,12,13,14,15)
unique(variable)

Answer 10

unique() removes duplicates
10 11 12 13 14 15

Question 11

Calculation with R

Write a function that only prints even numbers from this array:
variable <- c(1,2,3,4,5,6,7,8,9,10)

Answer 11

Question 12

Calculation with R

What is the output from this function?

Answer 12

0, 10, 20, 30

Question 13

Calculation with R

How does the ouput from the following function look like?

Answer 13

Question 14

Calculation with R

What is the meaning of “criterion = 5” in this function:

Answer 14

It is the default parameter that will be set if no paramter is handed over.

Question 15

Calculation with R

What is the output of this function:

Answer 15

1

Question 16

Calculation with R

What is the ouput of this function:

Answer 16

5,5,5,5,5,5,5,5,5,5

Question 17

Calculation with R

Add the code to built the following frame:

Answer 17

Question 18

Calculation with R

Show the function to list all index1 items of this table:

Answer 18

myFrame$index1

Question 19

Calculation with R

Write the R function to generate the following table:

Answer 19

Question 20

Calculation with R

What is the function of the $-Operator?

Answer 20

Table:
access of data frame columns

List:
access alement of list

Below a example for the list operation

Question 21

Calculation with R

Show the difference of this two operations:

Answer 21

Question 22

Calculating with R

Which function must be applied on “x” to get this result:
-3 8 -9 2 -1

Answer 22

diff( x )

Question 23

Calculating with R

Desribe the output of the following three functions:

c(3,10)
seq(4,10)
rep(5,10)

Answer 23

3 10
4 5 6 7 8 9 0 
5 5 5 5 5 5 5 5 5 5 

Question 24

Calculating with R

write the function to get the following output:

Answer 24

Question 25

You are working as a cashier at Cinemax. Chatting with your boss, they figured out that you are proficient in user studies on technology and asked you to help. They want to equip their cinemas with VR goggles for everyone. How do you evaluate if this is a good or a bad idea? Considering reasonable use, you have unlimited resources.

Task A: Craft a research question

Task B: Formulate at least one hypothesis

Task C: Sketch out a within-subjects experimental design. What are the dependent and independent variables? Describe experimental manipulations and metrics in detail.

Task D: Draw a potential plot of your expected results.

Task E: How do you know that your results are valid?

Task F: What are potential limitations of your experimental design? Name at least two.

Answer 25

A:Does the use of VR goggles have an effect on the user experience during a movie?

B:The utilization of VR goggles leads to an better user experience during a movie.

C:Within-Subject Design: We recruit 30 participants to watch a film with and without VR goggles. Each subject runs through each condition and we have to consider a appropriate randomization (order of film with and without VR goggles).
After watching a movie, the user has to fill the User Experience Questionnaire (UEQ) - every participant two times.

Independent Variables: VR goggles
Dependent Variable: Overall User Experience

D: see picture

E: 100% validity is never guaranteed, because we measure only a particular group. But we can use established questionnairs and verify if we measured what we want to measure.

F: The satisfaction provided by a film is subjective and in some cases age dependent.

We measure a particular, small group and therefore only a part of the society.

Question 26

How can eye tracking be used to boost performance, for example in rendering a VR scenario?

Answer 26

You can only render the spot where the user is looking.
The rest of the presented environment does not need to be very detailed.

Question 27

What are three types of eye-movement behavior that gaze interaction interfaces can rely on?

Answer 27

Fixation
Saccades
Smooth Pursuits