HELP! I need help on my stats-PLEASE!

[Leah]

Someone please help me with these-

Lower limit of .18

Upper limit of .16

This is the distribution.


TIA!!

[Real Estate Nate]

Someone please help me with these-

Lower limit of .18

Upper limit of .16

This is the distribution.


TIA!!

hi!

[slow99]

Someone please help me with these-

Lower limit of .18

Upper limit of .16

This is the distribution.


TIA!!

Huh?

[Leah]

Nm, we got it.

Ugh-this class is teh DEVIL!

[slow99]

I love me some statistics.

[LS1Goat]

Care to explain?

[Leah]

Care to explain?

I wouldn't even know where to begin. LOL I'm just keeping my head above water. Thank God Chili has been helping me! Buut...he's at work and in a meeting so can someone explain this to me, please??!?

9. What is the probability of obtaining three or fewer heads on eight tosses of a coin?

This is the explanation and I have the answer, just need to understand the process....UGH.

Use the normal curve to find the area to the left of the upper limit of 3 (3.5), which will include 3,2,1,0 heads

Answer is .363

[GE]

Answer is .363

No, the answer is 42.

[Leah]

No, the answer is 42.

Not according to the answer sheet.

[Leah]

Fucking really? With all the god damn geniuses on this board, not ONE of you know how to do this??

[Gargamel]

Sorry, Statistics is not included in my DFWM support contract...

Hit me up when you want to know what a glide slope or radar side lobe is....

[slow99]

You need to find a z score for a binomial probability event. In this case n is 8, p and 1-p are each .5. Standard deviation comes in at sq root of expected value times p... 1.41. Z score is then (3.5 - 4) ÷ 1.4 which is negative .35. Look at the z table for that z score and you see that the corresponding probability is 36.3%.

[Leah]

You need to find a z score for a binomial probability event. In this case n is 8, p and 1-p are each .5. Standard deviation comes in at sq root of expected value times p... 1.41. Z score is then (3.5 - 4) ÷ 1.4 which is negative .35. Look at the z table for that z score and you see that the corresponding probability is 36.3%.

You freaking ROCK! That's exactly what I needed. Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!Thank you!

[BERNIE MOSFET]

You can also treat it like a summation of probabilities; maybe not helpful in solving the problem, but why the answer is what it is:

Probability of getting:
3 out of 8 is .219 (56 of 256 permutations, not 3 out of 8)
2 out of 8 is .109 (28 of 256)
1 out of 8 is .031 (8 of 256)
0 out of 8 is .004 (1 of 256)

Added together is .363

The permutations are important because when you flip the coin 8 times, there are 8 ways, or opportunities, to only get one heads - 28 ways to get two, and so on.

[Leah]

You need to find a z score for a binomial probability event. In this case n is 8, p and 1-p are each .5. Standard deviation comes in at sq root of expected value times p... 1.41. Z score is then (3.5 - 4) ÷ 1.4 which is negative .35. Look at the z table for that z score and you see that the corresponding probability is 36.3%.

The only difference was that I have to subtract .5 from the z-score of -.35 in order to account for the upper limit. Z-score is .1368-.5= .3632.

Whew! Thanks for the help!