Sampling
Name 5 different types of sampling
-Random
-Cluster
-Quota
-Systematic
-Opportunity
-Stratified
What type of data is needed for Scatter Graphs?
Bi-Variable Data
What does 'mutually exclusive' events mean?
2 or more events that CAN NOT happen at the same time
What does 107.4 mean?
7.4% increase
What type of graph would you use for data changing over time?
Time Series Graph
Irina is investigating whether the percentage of the population of a country living in urban areas has an effect on the life expectancy in that country.
Suggest a hypothesis Irina could use for her investigation.
E.G.
Countries with higher urban populations have higher life expectancies.
What does correlation mean?
Correlation is the relationship between 2 variables.
Correlation does not mean causation.
What does 'independent' event mean?
One event is NOT affected by the previous event
What do Index number measure?
Percentage change from the Base year
What formula do we use for Histograms?
Frequency Density = Frequency/Class Width
Simran wants to investigate the amount of time students spent completing homework each week. She asks 30 girls and 40 boys in Year 10.
What is the sampling method and why?
Quota - as there is a fixed number of each gender being selected.
What are the two method to measure correlation?
PMCC
and Spearman's Rank (Correlation Coefficient)
(SRCC)
There are 6 rainy days in February (28days)
What is the absolute risk of it raining in February?
6/28 (=0.214 to 3sf)
What is the formula for weighted mean?
Miss will show on the board
What point would you plot for a Cumulative Frequency Graph
(End point, CF)
What is a control group?
What is a matching pair?
Control group - Test effectiveness of a treatment. Randomly select 2 groups. 1 group
What does correlation not mean?
Correlation does not mean causation
Name 2 types of Probability Distribution
- Binomial distribution
- Normal distribution
What is the difference between Index Numbers and Chain Based Index Numbers?
Index number are % change from the base year.
Chain based index numbers are % change from the previous year.
Name 3 types of measure of average
Name 3 types of measures of spread
measure of average - mode, median, mean
measure of average -IQR, range and skew
What are the 2 ASSUMPTIONS made during Pearson's Capture Recapture?
AND
What are the 2 things needed to RELIABLE/VALID made during Pearson's Capture Recapture?
Assumptions
-No population changes (death/births/migration)
-No tags fell off/ marks rubbed off
Reliable/Valid
- Big enough sample (bigger sample = more relaible)
- Enough time between samples
(1 day - too soon, 2 weeks - too long)
Irina is investigating whether the percentage of the population of a country living in urban areas has an effect on the life expectancy in that country.
Using statistical software, Irina finds that the gradient of the line of best fit should be 0.19
Interpret the gradient of the line of best fit.
For every 1% increase in Urban population, life expectancy increases by 0.19 years.
B(6, 0.3)
Calculate P(X = 2)
Give your answer to 3 decimal places
6C2 x 0.32 x 0.74
=0.324 (3dp)
Calculate the geometric mean and interpret your answer
Year Index Number
2015 - 102
2016 - 107
2017 - 97
This means that on average the percentage change from 2015 to 2017 is 1% increase each year.
What is the formula for comparative pie charts?
Miss will show on the board.