{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture11_print

Lecture11_print - Chapter 8 Inference on Proportions...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

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

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

Unformatted text preview: Chapter 8: Inference on Proportions Readings: Sections 8.1-8.2 1 Introduction • There is NO SPSS work in this chapter. We will do everything by hand. • In previous chapters (5, 6, 7) we looked at confidence intervals and hypothesis testing for problems involving means, where we have a quantitative variable. • For problems involving counts and proportions, we have a categorical (“Which?” or “Do you?” or “Yes or no?”) variable. Example 1 : a. Did you vote in the last election? The response would be either a “Yes” or a “No”. The variable is categorical, the response is the value the variable takes on for each unit/person. If I did a survey of this class, I could accumulate the count of “Yes” responses and describe this count as a proportion of the total. b. What academic year are you in at Purdue? The response would be either “Fresh- man”, “Sophomore”, “Junior”, or “Senior”. Again, I could accumulate the count of each and describe each as a proportion of the total. In both cases we are interested in estimating the unknown proportion, p , from a population. The statistic, ˆ p (sample proportion) estimates the population parameter p . Population and Sample proportions • In statistical sampling we often want to estimate the proportion, p , of “successes” in a population. “Success” is when the categorical variable takes on one particular value. We normally call whatever characteristic we are studying a “success.” – Population proportion : p = Count of successes in population Size of population – Sample proportion...
View Full Document

{[ snackBarMessage ]}

Page1 / 6

Lecture11_print - Chapter 8 Inference on Proportions...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon bookmark
Ask a homework question - tutors are online