CHAPTER 5 Flashcards
1
Q
what is a time series graph?
A
- a line graph with time plotted on the horizontal axis
2
Q
what is a general trend?
A
- the way that data changes over time
3
Q
what does a trend line show?
A
- the general trend of data
4
Q
what might variations in a time series graph be?
A
- a general trend (as shown by the trend line)
- seasonal variations (a pattern that repeats)
5
Q
what is variation in a time series graph following a regular time period called?
A
- seasonal variation
- days of the week or seasons of the year
6
Q
what is a moving average?
A
- an average worked out for a given number of successive observations
7
Q
what do the moving averages show?
A
- help show trends on a time-series graph
8
Q
where should you plot moving averages on a time series graph?
A
- midpoint of the time intervals that they cover
9
Q
should you join up the points for moving averages?
A
- no
10
Q
predicted value equation:
A
predicted value= trend line + seasonal variation
11
Q
seasonal variation at a point equation:
A
seasonal variation at a point= actual value - trend value
12
Q
another name for mean seasonal variation:
A
- average seasonal effect
