3.3.1 Quantitative sales forecasting Flashcards
Correlation:
- relationship between variable and how strong
e. g. positive, negative, none (none = close to 0) - stronger = closer to line of best fit (regression line)
- scatter diagram
- a statistical technique used to establish strength of relationship between 2 variables
dependant variable
y-axis
-being influenced
independant varibale
x-axis
-one causing other to change
Line of best fit/regression line
- forecast sales & identify factors influencing demand
- strong correlation = relationship used to make marketing predictions/decisions
positive correlation
- direct relationship
- close to 1
- as one increases so does other
e.g. sales & advertising or income & sales
negative correlation
- inverse relationship
- close to -1
- as one variable increases other decreases
e.g. price and demand or as interest rate rises there is a fall in demand for new house
4 Pros of using correlation to forecast sales:
1-predict sales & demand factor
2-link = influenced for benefit of business
3-simple technique & useful for tactical thinking
4-appears regularly = chance correlation exists
Cons of using correlation to forecast sales:
- uncertainty = wrong extrapolation
- past wont repeat (dynamic)
- doesn’t show cause and effect
- coincidental links (doesn’t casual links)
- shows link (hard to distinguish between cause and effect)
- need to find casual link by looking at other factors (treated with caution = impossible to isolate factors)
Extrapolation
- extending line of best fit (dotted line)
- predict future levels such as sales
- analysing trends in past data
3 Affects to extrapolation
1-new competitor
2-increase price
3-external factors
Pros of extrapolation to forecast sales:
- quick and easy to implement
- accurate = based on past sales trends (static)
- quantitative target to predict future sales
Cons of extrapolation to forecast sales:
- doesn’t account for external factors
- assumes past repeats itself - may not be likely
- not useful for some markets (dynamic) (fast moving consumer goods)
- not statistically valid
- ignoring significant outliers
Moving averages
- time series analysis
- statistical calculation of an underlying trend in data
3 period: (add 3 together divide by 3)
why is a moving average useful:
- useful when dealing with erratic/personal data
- average of multiple time periods
- minimises effect go extreme value as an average taken
- used to emphasise direction of a trend & reduce ‘noise’ that can confuse interpretation
Analysing markets
- looks at several periods at a time & averages out the data
- helps iron out all peaks/troughs in demand = gives more accurate figure of whether sales have risen/fallen in market over time