CNSL 503 EXAM MODULE 7 CORRELATIONAL
ANALYSIS AND LINEAR REGRESSION PRACTICE
QUESTIONS WITH ANSWERS
◉ An astronomer wants to observe a cloud of dust in a relatively
close part of the Galaxy. Unfortunately, this dust cloud is not located
in the direction of a crowded region of stars. What instrument would
be the most help in finding this cloud.
Answer: a sensitive infra-red telescope in orbit around the Earth
◉ The dust in the dust clouds in interstellar space consists of
Answer: tiny solid grains
◉ If a star is 20 parsecs away, its parallax must be:
Answer: 1/20th of an arcsecond
◉ The _____ is a slightly denser cloud inside the Local Bubble, inside
which the Sun also lies
Answer: local fluff
◉ Which of the following is NOT one of the reasons planets around
other stars are so difficult to detect?
, Answer: planets only form very late in the life of a star, just when it
is ready to die, and thus last only a very short fraction of the star's
life
◉ Why is it so difficult for astronomers to see new stars in the
process of birth?
Answer: all of the above (birth happens very quickly, so it is hard to
"catch" stars "in the act", most stars are born inside dusty clouds,
which block any light that may be coming from the stars, the size of a
newly forming star is typically quite small and thus hard to make out
and protostars which are not yet doing fusion do not give off a lot of
visible light)
◉ The higher the luminosity (intrinsic brightness) a Cepheid
variable is,
Answer: the longer the period of its variations
◉ How far away would a star with a parallax of 0.2 arcsec be from
us?
Answer: 5 parsecs
◉ The measurement of cosmic distances was helped tremendously
by the discovery, in the early part of the 20th century, that in
Cepheid variable stars, the average luminosity was related to:
Answer: the length of time they took to vary their parallax
ANALYSIS AND LINEAR REGRESSION PRACTICE
QUESTIONS WITH ANSWERS
◉ An astronomer wants to observe a cloud of dust in a relatively
close part of the Galaxy. Unfortunately, this dust cloud is not located
in the direction of a crowded region of stars. What instrument would
be the most help in finding this cloud.
Answer: a sensitive infra-red telescope in orbit around the Earth
◉ The dust in the dust clouds in interstellar space consists of
Answer: tiny solid grains
◉ If a star is 20 parsecs away, its parallax must be:
Answer: 1/20th of an arcsecond
◉ The _____ is a slightly denser cloud inside the Local Bubble, inside
which the Sun also lies
Answer: local fluff
◉ Which of the following is NOT one of the reasons planets around
other stars are so difficult to detect?
, Answer: planets only form very late in the life of a star, just when it
is ready to die, and thus last only a very short fraction of the star's
life
◉ Why is it so difficult for astronomers to see new stars in the
process of birth?
Answer: all of the above (birth happens very quickly, so it is hard to
"catch" stars "in the act", most stars are born inside dusty clouds,
which block any light that may be coming from the stars, the size of a
newly forming star is typically quite small and thus hard to make out
and protostars which are not yet doing fusion do not give off a lot of
visible light)
◉ The higher the luminosity (intrinsic brightness) a Cepheid
variable is,
Answer: the longer the period of its variations
◉ How far away would a star with a parallax of 0.2 arcsec be from
us?
Answer: 5 parsecs
◉ The measurement of cosmic distances was helped tremendously
by the discovery, in the early part of the 20th century, that in
Cepheid variable stars, the average luminosity was related to:
Answer: the length of time they took to vary their parallax
