Centre & Spread
Centre & Spread
Outliers
Challenge
100
Name the three measures of centre of a data set
Mean, median and mode
100
Name a measure of spread
Range
100
What is the definition of an outlier?
An outlier is a data point that is significantly smaller or larger than the rest of the data.
100
List 3 ways of collecting primary data
Any 3 of: observation, simulation, measurement, experiment or survey.
200
How do you calculate the mean?
Sum of all the values divided by the total number of values
200
How do you calculate the range?
Range = the highest number - the lowest number
200
What measure of centre is most appropriate for when there are no outliers in the data?
Mean or median
200
Describe the shape of this graph
Postively Skewed
This is because the tail goes to bigger numbers
300
What are the steps for working out the median?
First put the numbers in ascending order, then select the middle number. If there are two middle numbers you will need to find the mean of the two numbers to calculate the median.
300
What is the mode of this data set:
2 5 7 9 11 15 6 8 23 27 34 1 0 89
There is no mode because they all repeat once.
300
What can an outlier effect?
Outliers can affect the overall measures from a group of data, particularly the mean and range.
300
Average daily temperatures in a week:
22, 24, 21, 23, 24, 23, 40
What is the mean and median?
Mean = 25.29
Median = 21, 22, 23, 23, 24, 24, 40 = 23
400
What is the mean of this data set:
2 5 7 9 11 15 6 8 23 27 34 1 0 89
237 / 14 = 16.93
400
How do you calculate the median if it lies directly between two numbers?
Add the numbers together and divide them by 2
400
Identify the outlier in the data set below and state what measure of centre would remain unchanged by the outlier?
20, 17, 19, 22, 18, 17, 5
Outlier = 5
The MODE would remain unchanged.
400
Which would be more accurate to analyse this data set, mean or median?
60, 70, 20, 50, 35, 63, 74, 244
Median because their is an outlier which would affect the Mean
500
How do you find the mean from a frequency table?
Total of fx column / total of frequency column
500
What score would represent the median of a data set with 323 pieces of data.
The 162nd score
500
Identify the outlier and calculate the mean with and without the outlier for the below data set:
3, 2, 6, 4, 3, 5, 16
Outlier = 16
Mean with Outlier = 5.6
Mean without the Outlier = 3.8
500
Five numbers have a mean of 10.
Four of them are: 6, 9, 12, 8.
What is the missing number?
(6+9+12+8+x)/5=10
6+9+12+8+x=50
x=50-6-9-12-8
x=15