Elementary Statistics Exam 2 Updated Actual Questions And Verified Answers

ELEMENTARY STATISTICS EXAM 2
UPDATED ACTUAL QUESTIONS AND
VERIFIED ANSWERS

●● Is the following a probability model?
impossible event is
Answer: No ,because the probabilities do not sum to
2. zero


●● In a certain card game, the probability that a player is dealt a
particular hand is 0.43. Explain what this probability means. If you play
this card game 100 times, will you be dealt this hand exactly 43 times?
Why or why not?
Answer: The probability 0.43
means that approximately 43 out of every 100 dealt hands will be that
particular hand. No, you will not be dealt this hand exactly 43 times
since the probability refers to what is expected in the long-term, not
short-term.


●● Suppose you toss a coin 100
times and get 76 heads and 24
tails. Based on these results, what is the probability that the next flip
results in a head?

,Answer: 0.76


●● According to a certain country's department of education, 42.6% of
3-year-olds are enrolled in day care. What is the probability that a
randomly selected 3-year-old is enrolled in day care?
Answer: .426


●● A survey of 200 randomly selected high school students determined
that 68 play organized sports.
(a) What is the probability that a randomly selected high school student
plays organized sports?
(b) Interpret this probability.
Answer: (a) 0.34
(b) If 1,000 high school students were sampled, it would be expected
that about 340 of them play organized sports


●● In a certain game of chance, a wheel consists of 32 slots numbered
00, 0, 1, 2,..., 30
To play the game, a metal ball is spun around the wheel and is allowed
to fall into one of the numbered slots. (a) Determine the sample space.
(b) Determine the probability that the metal ball falls into the slot
marked 3.
Interpret this probability.

,(c)Determine the probability that the metal ball lands in an odd slot.
Interpret this probability
Answer: (a) The sample space is {00, 0, 1, 2,..., 30}.
(b) The probability that the metal ball falls into the slot marked 3 is
0.0313. If the wheel is spun 1000 times, it is expected that about
31 of those times result in the ball landing in slot 3.
(c)he probability that the metal ball lands in an odd slot is 0.4688. If the
wheel is is spun 100 times, it is expected that about 47 of those times
result in the ball landing on an odd number.


●● ) Would you consider it unusual to find a college student who never
wears a seat belt when riding in a car driven by someone else
Answer: Yes, because P(never)<0.05.


●● A probability experiment is conducted in which the sample space of
the experiment is S{9,10,11,12,13,14,15,16,17,18,19,20}. Let event
E={10,11,12,13,14,15}
and event F={14,15,16,17}.
List the outcomes in E and F. Are E and F mutually exclusive? 1)List the
outcomes in E and F.
(2) Are E and F mutually exclusive?
Answer: 1) { 14, 15 }
2) No, E and F have outcomes in common

, ●● A probability experiment is conducted in which the sample space of
the experiment is
S={7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18}, event F={8, 9, 10, 11, 12,
13}, and event G={12, 13, 14, 15}. Assume that each outcome is equally
likely.
1) List the outcomes in F or G.
2) Find P(F or G) by counting the number of outcomes in F or G
3) Determine P(F or G) using the general addition rule.
Answer: 1) F or G= { 6, 7, 8, 9, 10, 11, 12, 13}
2) P(F or G)=.667
3) P(F or G)= 0.5+0.333−0.167=0.666


●● 1) Outcome "and"
2) outcome "or"
3) Are E and G mutually exclusive?
Answer: 1) only the common numbers
2) all the numbers
3) Yes, because the events E and G have no outcomes in common.


●● A probability experiment is conducted in which the sample space of
the experiment is S={7,8,9,10,11,12,13,14,15,16,17,18}.
Let event E={7,8,9,10,11}.
1) List the outcomes in