Measures of Location and Spread

Question 1

What is the mean?

Answer 1

The true average.

Question 2

How do you calculate the mean?

Answer 2

The sum of the data / The number of data in the sample. OR Σx / n

Question 3

What is the mode?

Answer 3

The most popular value.

Question 4

How do you calculate the mode?

Answer 4

By selecting the value that appears the most.

Question 5

What is the median?

Answer 5

The value that is in the middle.

Question 6

How do you calculate the median?

Answer 6

By taking the number of data in the sample, halving it and choosing the data that is that number.

Question 7

Which averages are affected by extreme values?

Answer 7

Mean and Median.

Question 8

How do you calculate the mean in a frequency table?

Answer 8

Σxf / Σf

Question 9

What is the lower quartile?

Answer 9

The value of the data one quarter into the data set

Question 10

What is the upper quartile?

Answer 10

The value of the data three quarter into the data set

Question 11

What is the interquartile range?

Answer 11

The range of data from the lower quartile to the upper quartile.

Question 12

What is a percentile?

Answer 12

Where the data is split into 100 parts (like a percentage)

Question 13

If the data is discreet and we need to calculate quartiles, what do we do?

Answer 13

Divide it by 4 and find the number, if it’s not whole, round up. If it is whole, the number is halfway to the next number.

Question 14

If we have a coded value, how do we work out the original standard deviation?

Answer 14

Multiply or divide but do not add or subtract.

Question 15

How do you work out the standard deviation?

Answer 15

Mean of the squares - the square of the mean. Then square root the answer.