Tuesday, July 10, 2012

Practice for contingency tables and time problems

_____________Male____Female__row totals
col. totals___90_____________________grand total

Answer the following probability problems from the completed contingency table. Write the answers first as fractions then rounded to the nearest thousandth.

The inclusion exclusion rule tells us p(A UNION B) = p(A) + p(B) - p(A INTERSECTION B

p(Male) = _________ ~= __________

p(Male INTERSECTION Facebook) = _________ ~= __________

p(Male UNION Facebook) = _________ ~= __________

Time problems.

a) How many minutes in 3 days?

b) 560 hours is __________ days and ________ hours.

c) 8,086 seconds is ________ hours, ________ minutes and __________ seconds.

d) 8,086 hours is ________ weeks, ________days and __________ hours.

e) After a flu outbreak, a hospital has decided quarantine will last 66 hours. If it starts at 5:00 pm on Tuesday, give the day and time when it will be over.

Day: ________ time: ___________ a.m or p.m? __________

Prof. Hubbard said...

column totals: 90 90 180

time problems.

a) How many minutes in 3 days?
Answer: 3 x 24 x 60 = 4,320 minutes

b) 560 hours is __________ days and ________ hours.

560/24 = 23.333333...

.3333 = 1/3 and 24 x 1/3 = 8

23 days and 8 hours

c) 8,086 seconds is ________ hours, ________ minutes and __________ seconds.

8086/3600 = 2.24611111....
>DMS 2:14:46

d) 8,086 hours is ________ weeks, ________days and __________ hours.

8086 [A b/c] 24 = 336 11/12

11/12 x 24 = 22

336 [A b/c] 7 = 48

8,086 hours is 48 weeks and 22 hours.

e) After a flu outbreak, a hospital has decided quarantine will last 66 hours. If it starts at 5:00 pm on Tuesday, give the day and time when it will be over.

Answer: 66 [A b/c] 24 = 2 3/4
3/4 * 24 = 18

Adding two days to Tuesday puts us to Thursday at 5:00 pm. Adding 18 hours to 5pm puts us into the next morning, so the answer is Friday, 11:00 am.

Thanks to Elsy Tobar for pointing out errors in the answers.

Prof. Hubbard said...

______________M__F__row totals