Which of the following statements are correct?
(A) The daily opening prices of a stock for one year, arranged in chronological order, form a time series.
(B) The temperature of a place recorded every second by one sensor forms a multivariate time series.
(C) Time series analysis of a stock can help to find when the stock goes through peaks and troughs.
(D) A time series that records several variables and how they vary over time is a multivariate time series.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A), (C) and (D) only
A time series is a set of values of a variable recorded at successive times. It is univariate when only one variable is recorded and multivariate when several variables are recorded over time.
So daily stock prices in time order form a time series that shows its peaks and troughs, one sensor gives a univariate series, and several variables give a multivariate series.
Checking the statements
(A) The daily opening prices of a stock for one year, arranged in chronological order, form a time series. — Correct. They are values recorded at successive times.
(B) The temperature of a place recorded every second by one sensor forms a multivariate time series. — Incorrect. Only one variable (temperature) is recorded, so it is univariate.
(C) Time series analysis of a stock can help to find when the stock goes through peaks and troughs. — Correct. It shows the pattern of the prices over time.
(D) A time series that records several variables and how they vary over time is a multivariate time series. — Correct. This is the meaning of a multivariate series.