Representation and summary of data—location

Question 1

What are quantitative variables?

Answer 1

Variables associated with numerical observations

Question 2

What are qualitative variables?

Answer 2

Variables associated with non-numerical observations

Question 3

What is a continuous variable?

Answer 3

A variable that can take any value in a given range

Question 4

What is a discrete variable?

Answer 4

A variable that can take only specific values in a given range

Question 5

What are class boundaries?

Answer 5

The midpoint between the upper and lower limits of two consecutive classes

Question 6

What is the width of a class?

Answer 6

The difference between its boundaries

Question 7

What is the mode?

Answer 7

The most frequent value

Question 8

What is the median?

Answer 8

The middle value when sorted in ascending order

Question 9

How can, say, the third quartile be found?

Answer 9

Letting n equal the number of items; if 3n/4 is a whole number, it is the midpoint of the 3n/4 and the (3n/4)+1 values. Else it is the ⌈3n/4⌉ value

Question 10

How is grouped data always treated when estimating values from it?

Answer 10

As continuous data

Question 11

What is the mean?

Answer 11

The sum of all values divided by the number of values

Question 12

How is the mean of a sample notated?

Answer 12

x̄

Question 13

How is the mean of an entire population notated?

Answer 13

µ

Question 14

When should the mode be used?

Answer 14

When the data is qualitative

Question 15

When should the median be used?

Answer 15

When the data is quantitative and there are extreme values

Question 16

When should the mean be used?

Answer 16

When there are no extreme values

Question 17

How can the nth value of grouped data be estimated using interpolation?

Answer 17

l + w(n-c)/f where:

l is the lower boundary of the class containing the nth value;
w is the width of the class containing the nth value;
c is the cumulative frequency of the classes before the nth value's class;
and f is the frequency of the class containing the nth value

Question 18

What is coding?

Answer 18

The process of making a set of data simpler to handle

Question 19

If y=(x-a)/b, express x̄ in terms of ȳ

Answer 19

bȳ+a