Week 4

Question 1

How do you manually compute RT?

Answer 1

t1 =now();
awaitkey(‘s,l’);
t2 =now(); RT =t2 -t1;
text(“Yourreactiontime was: “+RT);

Question 2

Why can you not show a stimulus for 26ms?

Answer 2

becausescreensrefreshat specificrates

–E.g., aboutevery16.7 ms

Question 3

await() records the intended and actual presentation time, as well as other times

give four of these event variable e structures

Answer 3

● e.intendedTime: the intended waiting time, which is 33 (ms) here
● e.duration: the actual duration of waiting time, which may have been, for example, 34
or 39 (ms)
● e.delta: this is simply e.duration - e.intendedTime, included for convenience 
● e.timestamp: low-resolution time in ms that can be converted into a date and time of day

Question 4

How can you get RT quicker?

Answer 4

e.RT

Question 5

How do you know which key is pressed?

Answer 5

e.key

Question 6

What is the difference between log and store?

Answer 6

If you call log(e.RT,”RT”)many times, each time a new line of data is added, The store() function also works in the background, but overwrites its variable in the table.

Question 7

How may store() be useful?

Answer 7

store(1,”where”); // store bookmark. You can also use retrieve(“where”) to retrieve the last stored value. This is handy because ‘stored()’ values are available even after the subject has moved away from the experiment half-way through.

Sometimes you need to be absolutely surea piece of data is stored, before you want the script to proceed. Use store_now() for that

Question 8

How does the increase function work?

Answer 8

Increases the valuable of the variable by 1 e.g for assigning subjects to conditions

varsubject_id=increase(“Subject ID”,”script”);

Question 9

What does the following code do?

b.style(“color”,”grey”);

Answer 9

Make the text colour grey

Question 10

Why should styles be used sparingly?

Answer 10

There are many subtle differences between browsers’ implementation of styles

Question 11

Which style is particularly variable and how do you get around this?

Answer 11

font-family is particularly variable (missing fonts will be substituted by others!). Use images of words if you must use a specific font

Question 12

How do you make a large header within text?

Answer 12

text(“<h1>Instruction</h1>”);
–Opening bracket is like
–Closing bracket is like

Headers: <h1> to </h1><h6>, e.g.,</h6><h3>Medium-size header</h3>

Question 13

Give some other HTML tags

Answer 13

• Paragraph: <p>my text</p>
• Bold text: <b>bold text</b>•Italics: <i>italics</i>
• Span: <span>does nothing</span>
• Horizontal line: <hr> (N.B. single tag)
• List: <ul> <li>item 1</li> <li> </li></ul>

Question 14

What does the code

b.style(“opacity”,1);

do?

Answer 14

Makes it completely transparent

Question 15

How do you change the background colour?

Answer 15

main.style(“body-background-color”,”black”);

Question 16

How would you do a wait function for either click?

Answer 16

vare, response,
left = addblock(10,80,15,10).button("Yes"),
right = addblock(75,80,15,10).button("No");
waitfor
{
e = left.await('click');
response = "yes";
} or {
e = right.await('click');
response = "no";
}

Question 17

How would you make a button for people to press?

Answer 17

var right = addblock(75,80,15,10).button(“No”)

There are more arguments (see book) and you can also style a button:
b.button(“Back”,”navigation”,”backward”,”back_button”).style(“background-color”,”red”,”#back_button”);

Question 18

What do the following functions do?
select
radio
scale 
check

Answer 18

–select(dropdown)
–radio(forced choice of one option)
–scale(as radio but horizontal; LikertScale)
–check(boxes)

Question 19

What numbers would range(11) give?

Answer 19

0,1,2,3,4,5,6,7,8,9,10

Question 20

How would you combine these on one page?

Answer 20

Using startform(); and endform();

Question 21

Given this line of code

e = await(“click”);

what is the use of the e.timestamp property?

Answer 21

For returning a relatively low-resolution time in ms that can be converted into a date and time of day.