The
percentage of people who do their own income tax return is 87%. The percentage
of people who get a refund is 76%. The percentage of people who file their own
return and get a refund is 68%.
1)
What
percentage of people either do their own return or get
a refund? (95%)
2)
What
percentage of people who do their own return get a
refund? (78.16%)
3)
Are
those who do not do their own return more likely to get a refund than those who
do? (61.54% of those who do not do their own return get a refund. The answer is
no.)
4)
Does
getting a refund depend on whether or not someone does their own return? (P(refund | own return) does not equal P(refund). Yes, it
does depend)
A credit
card company conducted a survey with 10,000 people to determine if there is a
link between annual household income and credit card balances. These were the
results:
|
Balance|Income |
<$35K |
$35K
to under $50K |
$50K
to under $75K |
$75K
to under $100K |
$100K+ |
Total |
|
<
$500 |
107 |
508 |
191 |
0 |
0 |
806 |
|
$500
to under $1000 |
169 |
1377 |
826 |
254 |
64 |
2690 |
|
$1000
to under $5000 |
0 |
890 |
1419 |
911 |
254 |
3474 |
|
$5000+ |
0 |
254 |
805 |
1229 |
742 |
3030 |
|
Total |
276 |
3029 |
3241 |
2394 |
1060 |
10000 |
5)
What
percentage has a credit card balance under $1000? (34.96%)
6)
What
percentage of those who earn between $35,000 and $50,000 has a credit card
balance under $1000? (62.23%)
7)
What
percentage of those who earn less than $75,000 has a credit card balance under
$1,000? (48.55%)
8)
What
percentage of those who have a credit card balance of at least $1000 has an
annual household income of at least $50,000 (82.41%)
9)
Which
income group is the most likely to have a credit card balance of at least
$1000? What is the trend
in the percentage of each income group that has a credit card
balance of at least $1000? ($100K+ at 93.96%; the percentage increases with
each income group)
10)
If
you were writing a report, how would you write which income and balance categories
are mutually exclusive? (see key)
A recycling
firm collected recycling statistics for 3 cities A, B and C. The percentage of
the total number of residents in each city is 45% in A, 30% in B and 25% in C.
The percentage in each city that recycles is 12% in A, 18% in B and 30% in C. Of
those who recycle, the percentage that recycles milk jugs is 4% in A, 8% in B
and 40% in C.
11)
What
percentage overall recycles? (18.3%)
12)
What
percentage overall recycles milk jugs? (3.648%)
13)
Of
those who recycle, what percentage recycle milk jugs?
(19.93%)
Of those
with a university degree, 70.2% earn at least $60,000/year within 10 years of
finishing school. Of those without a university degree, the corresponding
percentage is 35.4%. Of the entire population, 24.6% have a university degree.
14)
What
percentage of the entire population earns at least $60,000/year within 10 years
of finishing school? (43.96%)
15)
Of
those who earn less than $60,000/year within 10 years of finishing school, what
percentage don’t have a university degree? (86.92%)
16)
An
accounting firm wants to have a password system in which the users can combine
both letters and numbers, but none can repeat. If the password is 6 characters
long, how many possible passwords are there? (1,402,410,240)
17)
If
the password must begin and end with a letter and none can repeat, how many
possible passwords are there? (723,465,600)