The sale of ice creams is higher in summer than in winter is an example of

Irregular variations in a time series is :

The number of letters posted in a certain city on each day for a week is given as follows: 40, 55, 28, 25, 31, 52, 43. Which of the following is not an entry in the three-day moving averages?

The rise in prices before Diwali is an example of

For the given five values, 13, 17, 21, 22, 32; the 3-year moving averages are:

Let $y = 138.86 + 7.64(x - 2021)$ be a straight line of best fit by using least square method to the following data:

Then the trend value for the year 2024 is:

In the month of January, the number of cases diagnosed of influenza epidemic are given in the following table

The 3-day moving averages are: