Measures of location and spread

Question 1

What is a ‘measure of location’?

Answer 1

A single value that describes a position in a data set

Question 2

What is a ‘measure of central tendency’?

Answer 2

If the measure of location describes the centre of the data.

If the number is in the middle of the data set

Question 3

When data are presented in a grouped frequency table you can use a technique called ___________ to estimate the median, quartiles and percentiles. When you use interpolation, you are assuming that the data values are ___________ ___________ within each class.

Answer 3

When data are presented in a grouped frequency table you can use a technique called interpolation to estimate the median, quartiles and percentiles. When you use interpolation, you are assuming that the data values are evenly distributed within each class.

Question 4

What are the three measures of spread?

Answer 4

Range
IQR
Interpercentile range

Question 5

What is the Interpercentile range?

Answer 5

The difference between the values for two given percentiles

Question 6

What is coding?

Answer 6

A way top simplify data to make it easier to deal with

Question 7

If the coding formula is:
x - a
——–
b

Then how do you find the mean of the coded data?

Answer 7

x̅ - a
y = ——-
b

Question 8

If the coding formula is:
x - a
——–
b

Then how do you find the standard deviation of the coded data?

Answer 8

σ = σ/b

Question 9

How do you find the mean of the original data when given the coding formula?

Answer 9

x̅ = bȳ + a

Question 10

How do you find the standard deviation of the original data when given the coding formula?

Answer 10

σ = σ * b

Question 11

True or False:
Adding or subtracting constants does not affect how spread out the data is, so you can ignore the ‘-40’ when finding the standard deviation for x.

Answer 11

True