{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CI_mu_sp08 - Confidence Intervals for a Population Mean t...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Confidence Intervals for a Population Mean μ ; t distributions t distributions t confidence intervals for a population mean μ Sample size required to estimate μ
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The Importance of the Central Limit Theorem When we select simple random samples of size n, the sample means we find will vary from sample to sample. We can model the distribution of these sample means with a probability model that is , N n μ σ
Image of page 2
Since the sampling model for x is the normal model, when we standardize x we get the standard normal z n x z σ μ - = n x SD σ = ) ( that Note
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
If μ is unknown, we probably don’t know σ either. The sample standard deviation s provides an estimate of the population standard deviation σ For a sample of size n, the sample standard deviation s is: n − 1 is the “degrees of freedom.” The value s/√n is called the standard error of x , denoted SE(x). n x SD σ = ) ( - - = 2 ) ( 1 1 x x n s i n s x SE = ) (
Image of page 4
Standardize using s for σ Substitute s (sample standard deviation) for σ n x z μ - = σ σ σ σσ σ σ ssss σ s ss s n x z σ μ - = Note quite correct Not knowing σ means using z is no longer correct
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern