Which of the following are the components of a time series?

(A) Cyclic component

(B) Regular component

(C) Seasonal component

(D) Economic component

Choose the correct answer from the options given below:

A time series is data collected over time, such as daily temperature, monthly sales, or yearly population.

Time series has four standard components:

1. Trend (T) - Long-term direction over years
2. Seasonal (S) - Regular pattern that repeats in fixed periods (every summer, every December, etc.)
3. Cyclic (C) - Wave-like patterns over long periods (business cycles, economic ups and downs)
4. Irregular/Random (I) - Unpredictable, random variations

Evaluating each option:

(A) Cyclic component - This is a standard component ✓

(B) Regular component - This is not a standard term in time series ✗

(C) Seasonal component - This is a standard component ✓

(D) Economic component - This is not a standard component. Economics may affect time series, but "Economic component" is not a technical term ✗

The valid components are (A) and (C) only.

Therefore, the answer is Option 1.

Memory aid: T-S-C-I = Trend, Seasonal, Cyclic, Irregular (the only 4 components)