## Times Series Exercise

 1 Use the time series shown to answer the following questions: a. What was the sales figure for the second quarter of 1998? b. Which quarter and year produced the highest sales figure for Polar Cream Ltd? c. Which quarter and year produced the lowest sales figure for Polar Cream Ltd? d. Give a reason why sales are lowest in the third quarter of each year. e. Why do you think that sales peak in the first quarter of each year? f. Give some figures to show why the manager of Polar Cream Ltd is justified in saying that sales are rising. g. Make a prediction for the company's sales for the third quarter of the year 2000.

2. The table below shows the number of videos issued (to nearest 5) from a video library over a two week period.

 Day of Week M Tu W Th F Sa Su M Tu W Th F Sa Su Number of books issued 35 55 65 105 130 155 140 45 55 70 95 150 195 140

a. Draw a time series graph for the above data.
b. Comment on the shape of the graph and give reasons for it.

3. Figures for the total population of New Zealand taken from Census results between 1901 and 1981 are given below.

 Year of Census Population of New Zealand (millions) 1901 0.8 1911 1.1 1921 1.3 1936 1.6 1956 2.2 1966 2.7 1976 3.1 1981 3.2

a. Draw a time series graph for these figures. Take care with the values on the time axis.
b. Comment on the trend these figures show and make a prediction for New Zealand's population at the 1986 Census.