Probability & Statistics
Exam Review #1
Name___________________________
1. Determine if it is descriptive or
inferential statistics.
5. Classify as cluster, systematic,
random, or stratified.
a. According to the Census Bureau,
20% of all American workers get to
work by carpool.
a. Every 7th customer entering a mall
is asked to do a survey.
b. Allergy therapy may make bees go
away.
b. A class is divided into groups and
a few from each group are selected
to present a project.
c. The average salary at the company
is $55,000 per year.
c. Put all the names in a hat and draw
out 8 names.
2. Classify as nominal, ordinal, discrete,
or continuous level data.
a. salaries of cashiers at Bi-Lo
d. We will survey everyone in two of
the schools out of the district.
6. Find the mean.
x
6
3
8
5
3
b. rankings of football teams
c. temperature of popcorn popper
d. marital status on a survey
f
36
9
64
25
9
3. Classify as qualitative or quantitative.
7. Find the standard deviation.
a. married or not married
b. number of books in your locker
c. rocks divided into categories
d. weight of a rock
4. Classify as continuous or discrete.
Class
16-20
20-24
24-28
28-32
f
3
7
12
8
8. Complete the table for the probability
distribution.
a. weight of your books
b. number of tv’s you own
c. time it takes to run the 50
d. number of races won
x
P(x)
1
0.2
2
0.3
3
0.4
4
9. If a woman can select one of three nail
polish colors, one of five lipstick
shades, and one of four blush shades,
how many different combinations can
she make?
10. The probability that Sam will be
accepted by the college of his choice
and obtain a scholarship is 0.35. If
the probability that he is accepted by
the college if 0.65, find the prob.
that he will obtain a scholarship given
that he is accepted by the college.
11. If 60% of all women are employed outside the home, find the probability
that in a sample of 29 women,
a. Exactly 15 are employed.
b. At least 10 are employed.
c. At most 10 are employed.
12. Find the area under the standard
normal distribution for each.
a.
b.
c.
d.
between -1.22 and 1.05
between 1.12 and 2.03
to the left of 1.23
to the right of 1.78
13. On the daily run of an express bus,
the avg. number of passengers is 48.
The standard dev. is 3. Assume the
variable is normally distributed. Find
the probability that the bus will have
a.
b.
c.
d.
between 36 and 40 passengers.
less than 42 passengers.
more than 48 passengers.
at most 47 passengers.
14. How many ways can a president, vicepresident and secretary be selected
in a club with 30 members?
15. The probability of owning a surfboard
is 0.43, of owning a skateboard is
0.38, and of owning both is 0.28.
what is the probability of owning a
surfboard or a skateboard?
16. An organization wants to sponsor a
contest to see who can color 40 pages
the fastest. The average time it takes
to color the pages is 58.6 minutes,
with a st. dev. of 4.3 minutes. If the
organization decides to hire the top
20% of the participants, what is the
cutoff time for the contest?
Assume the variable is normally
distributed.
17. Estimate with 95% confidence the
number of people who own home
computers. A previous study shows
40% of those interviewed had one.
Researchers want to be accurate to
within 2% of the true proportion.
18. A sample of 6 adult elephants had an
average weight of 12,200 pounds,
with a sample st. dev. of 1.6. Find the
90% confidence interval of the true
mean.
19. The avg. SAT score in math is 483,
with a st. dev. of 100. A special
course states that it can increase
scores. A sample of 32 students
completed the course, and the avg. of
their scores was 494. At  = 0.05,
what is the test statistic?
20. Describe the difference between
classical and empirical probability.