ch10_notesV_2011

ch10_notesV_2011 - Chapter 10 Statistical Inference about...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 10 Statistical Inference about Means and Proportions with Two Populations Outline: Estimation of the difference between means of two populations: 1. Point estimator of the difference between the means of the populations. 2. Sampling distribution of the point estimator. 3. Interval estimate of μ 1 2 : Large Sample Case. 4. Interval estimate of μ 1 2 : Small Sample Case. Hypothesis tests about the difference between the means of two populations: Independent Samples. Inferences about the difference of means: Matched Samples. Point Estimator for μ 1 2 1. Select a simple random sample of size n 1 from population 1 and compute . 2. Select a simple random sample of size n 2 from population 2 and compute . 1
Image of page 1

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

View Full Document Right Arrow Icon
2 3. Compute the point estimator: . 2
Image of page 2
Sampling Distribution of : Expected Value of: The point estimator of the difference of means () is Standard Deviation of: (Aside) An easier way to remember is that where σ 1 = standard deviation of population 1 σ 2 = standard deviation of population 2 n 1 = sample size from population 1 n 2 = sample size from population 2 3
Image of page 3

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

View Full Document Right Arrow Icon
4 Interval Estimate of μ 1 2 : Large Sample (n 1 > 30 and n 2 > 30) σ 1 known and σ 2 known where 1- α is the confidence coefficient σ 1 unknown and σ 2 unknown where 4
Image of page 4
Example: Par, Inc. Par, Inc. is a manufacturer of golf equipment and has developed a new golf ball to provide extra distance . In a test of the driving distance using a mechanical device, a sample of golf balls was compared with a sample of golf balls from a competitor (Rap, Ltd.) Sample Statistics Sample #1 Sample #2 Par, Inc. Rap, Ltd . Sample Size n 1 = 120 balls n 2 = 80 balls Mean = 235 yards = 218 yards Standard Dev. s 1 = 15 yards s 2 = 20 yards Point Estimate of the difference between the populations, where μ 1 is the mean driving distance of golf balls from Par, Inc.; μ 2 is the mean driving distance of golf balls from Rap, Ltd. Point Estimate of Point Estimate of standard deviation of is given by 95% confidence interval: 5
Image of page 5

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

View Full Document Right Arrow Icon
6 6
Image of page 6
Interval Estimate of μ 1 2 : Small Sample (n 1 < 30 and/or n 2 < 30) Assumptions: 1.
Image of page 7

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

View Full Document Right Arrow Icon
Image of page 8
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