250 employees in an organization were surveyed about their hair color and height. The data collected is presented in the table. If a person is selected at random, what is the probability that the person is at least 175 centimeters tall?

0.296

0.344

0.360

0.656

Question

250 employees in an organization were surveyed about their hair color and height. The data collected is presented in the table. If a person is selected at random, what is the probability that the person is at least 175 centimeters tall?

0.296

0.344

0.360

0.656

anonymous · Answer

attachment

mathmale · Answer

Because of the format of the table, I see this problem may include some "conditional probability."  Familiar with that?

anonymous · Answer

not really

anonymous · Answer

but I believe the answer is C, atleast what I got

mathmale · Answer

How many people are 175 to 180 cm in height?

anonymous · Answer

90

mathmale · Answer

True, and how many are taller than 180 cm?

anonymous · Answer

74

mathmale · Answer

Yes, and how many are 175 cm tall or taller?

anonymous · Answer

90?

mathmale · Answer

No.  Think.

mathmale · Answer

what does "or taller" mean?

anonymous · Answer

you already asked me how many are 175 or taller and I answered 90

mathmale · Answer

You were right.  This new question is different from before.

mathmale · Answer

How many people are between 175 cm and 300 cm tall?

anonymous · Answer

I dont understand what youre asking

anonymous · Answer

the graph stops at 180?

mathmale · Answer

I know.  I'm trying to get you to think.

anonymous · Answer

IM SO CONFUSED

mathmale · Answer

90 are 175 to 180 cm tall.
74 are above 180 cm.  That could include people who are 230 cm. tall, right?

mathmale · Answer

OK.  Use this info to answer my question:  how many people are 175 cm tall or taller?

anonymous · Answer

74?

mathmale · Answer

add together 90 and 74.  Does this help?

anonymous · Answer

yes holy crap thank you, so 164?

mathmale · Answer

yes.   so, 164 people are 175 cm tall or taller.    what does holy crap look like?   ;)

anonymous · Answer

so how do I figure out the answer

mathmale · Answer

how many peoople are there all together?

anonymous · Answer

250

mathmale · Answer

what fraction of 250 peoople is 164 people?

anonymous · Answer

would I just divide 250 by 164?

mathmale · Answer

no, 164 by 250.;

anonymous · Answer

0.656

mathmale · Answer

now compare that result to the four given answers.

anonymous · Answer

Its D

anonymous · Answer

can you help me with one more?

anonymous · Answer

Its using the SAME graph we just used

mathmale · Answer

Right.   I like to teach by asking questions so that you can discover answers for y ourself.
Hope you didn't get too frustrated.

sure, let's see the next problem

anonymous · Answer

250 employees in an organization were surveyed about their hair color and height. The data collected is presented in the table. If a person taller than 180 cm is chosen at random what is the probability that the person has black hair?

anonymous · Answer

& thats with the same graph we were already using

mathmale · Answer

This is conditional probability.
have you worked problems in conditional probability before?

anonymous · Answer

I think I may have

mathmale · Answer

OK.  We are told that the person chosen is taller than 180 cm, right?

anonymous · Answer

yes

mathmale · Answer

OK, now look at the table again.  how many are taller than 180 cm?

anonymous · Answer

74

mathmale · Answer

right.  now, that 74 is broken down into categories.  Do you see one category labeledd  "black hair?"

anonymous · Answer

yes 29

mathmale · Answer

OK.  We don't give a darn about anybody who's not over 180 cm tall.
So, y ou concentrate on that group of tall people only.  Forget the 250.
You say, of 74, 29 have black hair?

anonymous · Answer

yes so divide 29 by 74?

mathmale · Answer

yes.  and then compare your result to the possible answers.

anonymous · Answer

I got 0.391 and the one answer is 0.392

anonymous · Answer

Do I just round up?

mathmale · Answer

close enuf.

mathmale · Answer

Be sure you understand the reasoning here.

anonymous · Answer

thank you so much for the help

anonymous · Answer

hey

mathmale · Answer

of the people taller than 180 cm, how many do NOT have black hair?

anonymous · Answer

quick question

mathmale · Answer

I'll be quick, I promise.

anonymous · Answer

last one LOL

mathmale · Answer

Oh, really?
what's the last qu?

anonymous · Answer

Based on the data in this two-way table, what is the probability of a girl having above-average grades?

0.29

0.51

0.58

0.60

anonymous · Answer

Gender/Grade	Below Average	Above Average	Total
Boy	14	23	37
Girl	16	22	38
Total	30	45	75

anonymous · Answer

can you help me real quick?

mathmale · Answer

this is also conditional probability.  You are told that the person chosen at random is a girl.  Forget aboput those boys; they don't count.

mathmale · Answer

Now, how many girls are there?

anonymous · Answer

in total?

anonymous · Answer

or with above average grades

mathmale · Answer

total number of GIRLS only.

mathmale · Answer

Look at the table, really quick.

anonymous · Answer

38

mathmale · Answer

concentrating on girls ONLY, how many of the students have above average grades?

mathmale · Answer

synskii?

mathmale · Answer

sTILL THERE?  surely would appreciate having your full attention.