binomial probability question: "In a clinical trial, 94 subjects were treated with...

[melodymegs]

binomial probability question: "In a clinical trial, 94 subjects were treated with...

Hi, I am having a hard time solving this problem, I am new to stats.
"In a clinical trial of the cholesterol drug Lipitor, 94 subjects were treated with 80 mg of Lipitor, and6.4% of them developed headaches, so n = 94 and p = 0.064. Assume that the procedure yields a binomialdistribution with n trials and the probability of success for one trial is p. Find the mean  and standard deviation. Also, find the minimum usual value   2 and the maximum usual value  + 2. "

So far I have my n-94 and p-.064. What are my next steps? Any help is appreciated, I have a whole assignment I am having difficulty with.

 

[stapel]

Hi, I am having a hard time solving this problem, I am new to stats.

"In a clinical trial of the cholesterol drug Lipitor, 94 subjects were treated with 80 mg of Lipitor, and 6.4% of them developed headaches, so n = 94 and p = 0.064. Assume that the procedure yields a binomial distribution with n trials and the probability of success for one trial is p. Find the mean  and standard deviation. Also, find the minimum usual value   2 and the maximum usual value  + 2. "

So far I have my n-94 and p-.064. What are my next steps? Any help is appreciated, I have a whole assignment I am having difficulty with.

I'm sorry, but the special characters you used are showing up here as boxes filled with tiny hexadecimal values (I think?). Please reply with the spelled out contents immediately after "Find the mean" and "and standard deviation", and around the two numerical expressions (?) in the last sentence.

When you reply, please explain what you mean by "my n-94 and p-.064" (in particular, what these subtractions mean) and state whether your class has yet covered binomial distributions, with its methods and formulas. Thank you!

 

[HallsofIvy]

Do you know what the "binomial distribution" referred to is? With probability p of success in each trial, the probability of m successes in n trials is \(\displaystyle \begin{pmatrix}n \\ p \end{pmatrix}p^m(1- p)^{n-m}\). The expected value is pn and the standard deviation is \(\displaystyle \sqrt{np(1- p)}\). Here, n= 94 and p= 0.064 as you say so the probability of m success is \(\displaystyle \begin{pmatrix}94 \\ m\end{pmatrix} (.064)^m(.936)^{94- m}\). The expected value is \(\displaystyle 94(.064)\) and standard deviation \(\displaystyle \sqrt{(94)(0.64)(.936)}\). I don't know what you mean by "usual value".

 

[Harry_the_cat]

Hi, I am having a hard time solving this problem, I am new to stats.
"In a clinical trial of the cholesterol drug Lipitor, 94 subjects were treated with 80 mg of Lipitor, and6.4% of them developed headaches, so n = 94 and p = 0.064. Assume that the procedure yields a binomialdistribution with n trials and the probability of success for one trial is p. Find the mean(mu) and standard deviation (sigma).Also, find the minimum usual value (mu - 2sigma)and the maximum usual value (mu + 2sigma). "

So far I have my n=94 and p=.064. What are my next steps? Any help is appreciated, I have a whole assignment I am having difficulty with.

I'm guessing you mean the above (in red), though I've never before heard the phrase "usual value" but I guess it makes some sense.

Once you have calculated mean and standard deviation (HallsofIvy has helped you there), use the "formulae" above to calculate the min and max "usual" values.