In the month of January, the number of cases diagnosed of influenza epidemic are given in the following table | Date | 1 | 2 | 3 | 4 | 5 | 6 | 7 | |---|---|---|---|---|---|---|---| | Number of cases | 2 | 0 | 5 | 12 | 20 | 27 | 46 | The 3-day moving averages are:

In reference to the Time Series Analysis, which of the following statements are correct?

A. Variations which generally occur due to the general tendency of the data to increase or decrease, are known as secular variations.

B. Variations which occur due to change in climate, wheather conditions, festivals etc. are known as seasonal variations.

C. Variations which occur due to some unpredictable forces are known as cyclic variations.

D. Variations which occur due to booms and depressions are known as irregular variations.

Choose the correct answer from the options given below:

For predicting the straight line trend in the sales of cars (in thousands) on the basis of 5 consecutive years' data, the company makes use of a 3-year moving averages method. If the sales of the cars for respective years are 15, 24, 18, 33 and 42 respectively, then which of the following averages will not be computed?

If three year moving averages for five data items given by 16, 18, 20, 10, 21 are $x$, $y$ and $z$ respectively, then:

Which of the following is not a component of the time series?

If $y = 38.85 + 7.64(x - 2020)$ is the equation of the straight line trend for the following data:

The trend value for the year 2021 by least square method is:

For a straight line trend $y_t = a+bx$ for $n$ data by the method of least squares if, $n=8, \sum y=47.8, \sum xy=4.3$ and $\sum x^2=42$, then $y_t$ at $x=-3.5$ is _____.

[where $y_t$ represents trend value of y]