The Official Math/Physics/Whatever Homework questions thread

[kingofsurvivorbb]

I think this is a super simple question, but I want to be 100% sure.

For each of the following combinations of n and p, find the mean of the sampling
distribution of the sample proportion Phat. (Round your answer(s) to 3 decimal places.)
A) n = 100; p = 0.4
E(Phat) = _________
B) n = 200; p = 0.94
E(Phat) = _________
C) n = 2000; p = 0.08
E(Phat) = _________

a) .4
b) .94
c) .08

correct?

[Vael]

what's "phat"?

[kingofsurvivorbb]

p-hat

[Cueballmania]

I find it interesting that most of the statistics questions assume we know their notation and they don't want to define what anything is.

[kingofsurvivorbb]

so expected value of p-hat. I'm not sure if it's whether they want .94 or 200*.94=188 for all of them.

[Kittens]

Originally Posted by Cueballmania

I find it interesting that most of the statistics questions assume we know their notation and they don't want to define what anything is.

My high school statistics course was all about being able to repeat textbook examples with different numerical values. You didn't actually have to understand anything at all to get 90%+.

[asd16]

how do you get the answer for this problem, show work

A password consists of four letters followed by three digit number.

A) How many passwords are possible if there are no restrictions
answer: 456,976,000

B) How many passwords are possible if none of the letters or digits can be repeated?
answer: 258,336,000

[Cueballmania]

How many letters are there? How many numbers? How do you find the probability of independent things?

[asd16]

26 letters, 10 numbers

[acehole60]

Originally Posted by asd16

26 letters, 10 numbers

Here's another hint. If it was one letter and one number in the password and you had to find how many combinations was possible, you would count them by saying: for each of the 26 letters, there are 10 numbers. I.e. for A there is 0,1,2...,10. Same for B, C,...

So, total number of combinations is 26*10 = 260.

Now, apply the thinking to your own problem.

[non-self-weighter]

Here's yet another hint. People don't respond so well when you say: "Here's a problem. Solve it for me and show your work."

Try as best as you can and let us know where you get stuck. First, show your work.

[Wyman]

Originally Posted by non-self-weighter

Here's yet another hint. People don't respond so well when you say: "Here's a problem. Solve it for me and show your work."

Try as best as you can and let us know where you get stuck. First, show your work.

Yeah, some regs in this thread are more tolerant of this than others (I think I vary from day to day). But this isn't a "do my homework for me" thread. It's a "help me with my homework" thread.

We want to see your ideas and thought processes so that we can help you understand how to do the problem.

[Sven2812]

Hey,

I've got this problem from my calculus 2 class.

is the equiation x^y=y^x solvable after one of the variables around the points (e,e), (2,4)?

I don't have any idea what to do here.
I mean I can see that those two are obvious solutions, cause any x=y is a solution and another one would be (-2,-4), but that doesn't really help me


We just did constrained extremums and inverse functions if that helps.

[Wyman]

Originally Posted by Sven2812

is the equiation x^y=y^x solvable after one of the variables around the points (e,e), (2,4)?

I don't even know what this sentence means.

[Sven2812]

Originally Posted by Wyman

I don't even know what this sentence means.

lol english is tough
ok we got x^y=y^x

so now we wanna write the equation in terms of:
x=f(y) or y=f(x)

but not everywhere just in a small area around (e,e) and (2,4)