Question

Need Help fast!!!


use the following table to answer the questioin...
X = P(X)
A = 0.30
B= 0.20
C = ?
D = 0.28
Find P(A and D) assuming that A and D are independent.

Answer 1

P(A and D) = P(A) * P(D) where events A and D are independent

Answer 2

So just multiply the corresponding probabilities

Answer 3

0.30 * 0.28 = 0.084

Answer 4

you nailed it

Answer 5

Thanks! :)

Answer 6

yw

Answer 7

what about this one?
you toss 2 coins. find P ( at least 1 tail is tossed)

Answer 8

What's the sample space look like? Any ideas?

Answer 9

TT TH HT HH

Answer 10

good

Answer 11

How many have at least one tail?

In other words, how many have one T or two Ts?

Answer 12

3

Answer 13

out of how many?

Answer 14

4

Answer 15

Good, so

P ( at least 1 tail is tossed) = 3/4

Answer 16

but since their are 2 coins, wouldn't it make it 6/8?

Answer 17

no, there are only 4 possible ways to toss 2 coins

Answer 18

and there are only 3 ways to get at least one tail

Answer 19

besides, 6/8 reduces to 3/4 anyway

Answer 20

oh okay :) for some reason, it keeps giving me the answer, 7/8??

Answer 21

really? hmm odd

Answer 22

are you sure that it isn't 3 coins?

Answer 23

if you toss 3 coins, then P(at least one tail) = 7/8

Answer 24

ohhhh, I see now :P

Answer 25

this is because the total possible ways to toss 3 coins are

HHH
HHT
HTH
HTT
THH
THT
TTH
TTT

and 7 of these total 8 have at least one tail.

Answer 26

ahhh, okay :) hmmm what about this?

When tossing 2 coins, P ( at least 1 head) = P(not all tails) True or False?

Answer 27

Well we know that P ( at least 1 head) = 3/4 from last time right?

Answer 28

yes

Answer 29

What about P(not all tails)?

Answer 30

= 1/4

Answer 31

what is P(all tails)?

Answer 32

0/4?

Answer 33

Remember, we have

HH
HT
TH
TT

How many of the 4 are all tails?

Answer 34

4

Answer 35

HH has all tails?

Answer 36

so 3?

Answer 37

HT is all tails?

Answer 38

1?

Answer 39

good, only TT is all tails

Answer 40

so P(all tails) = 1/4

Answer 41

Now we can use this idea to find P(not all tails)

Answer 42

2/4

Answer 43

close, but not quite

Answer 44

P(not all tails) = 1 - P(all tails)

Answer 45

0?

Answer 46

P(not all tails) = 1 - P(all tails)

P(not all tails) = 1 - 1/4

P(not all tails) = ???

Answer 47

0.75

Answer 48

or 3/4

Answer 49

so because P(not all tails) = 3/4 and P ( at least 1 head) = 3/4, we can say that


P ( at least 1 head) = P(not all tails)

Answer 50

So that answer is indeed True

Answer 51

you got it

Answer 52

Thanks for your help! Really appreciate it! :)

Answer 53

you're welcome

Answer 54

I have trouble figuring these types of questions out, could you help? his is an example of which of the following sampling techniques? HELP?
A chef wants to open a new Italian restaurant. He wishes to find out which kinds of pasta (spaghetti, linguini, or penne) will be the most popular with potential customers.

He hires a polling organization to survey the market. The company builds a telephone survey list by selecting one person at random from the first page of the telephone book, who turns out to be the 123rd person on the page. The company then fills out the list by adding the 123rd person on every page of the book.


A.Systematic sample
B.Stratified sample
C.Simple random sample (SRS)
D.Cluster sample
E. Convenience sample

Answer 55

Any ideas?

Answer 56

I'm thinking its systematic because, hes choosing the 123rd person, and then 123td person on every page of the book?

Answer 57

you got it, very nice

Answer 58

thanks !

Answer 59

yw

Answer 60

How do you find the mean, using a histogram?

Answer 61

each value under the histogram represents a value in the data set

the heights of each histogram represent how frequent each value in the data set occurs

making sense so far?

Answer 62

Yes, and it also says this histogram as a class width of 1

Answer 63

So you simply multiply each value under the histogram by the corresponding height...then you add up each product

Finally, you divide that last result by the total number of values (ie the sum of the frequencies)

Answer 64

Okay, so the Height is 5.....
and the width is 10 but there are only 9 being used.
so 1 * 2
3 * 4
4 * 5
5 * 4
6 * 2
7 * 1
8 * 1
9 * 1
10 * 1

Answer 65

Multiply all those out, add up the results and divide that by the sum of the heights

Answer 66

632 / 15
Is this right?

Answer 67

hmm I'm getting something different, but that could mean that I'm missing something (since I can't see the histogram)

Answer 68

well, I'll see if I can post it here... but basically it has a height of 5, and a width of 10 but only nine blocks are used.

Answer 69

which one has a height of 5?