{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

13_(Ch12)_Estimation_Outline

# 13_(Ch12)_Estimation_Outline - 1 2 3 4 5 6 7 8 9 10 11 12...

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

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

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

Unformatted text preview: 11/23/10 1 2 3 4 5 6 7 8 9 10 11 12 Psychological Statistics - Estimation PSY 207 Overview •  Estimation – Point estimation – Interval estimation – Confidence intervals •  Constructing confidence intervals •  Sample size and confidence intervals •  Confidence vs. Precision Estimation •  We have previously discussed testing hypotheses about a population •  We may also be interested in estimating a population mean... – ... to determine the size of an effect – ... to determine information about a population •  We can use sample characteristics and test statistics to estimate population means Two types of estimates Point estimates Interval estimates Confidence Intervals •  Range of values within which we are reasonably confident the population mean lies. •  In fact, we can specify exactly how confident we are. Interval estimates based on t Sampling distribution of the mean Steps for a confidence interval 1.  Calculate sample characteristics: 1.  Sample mean 2.  Sample variance 2.  Select an acceptable confidence level (e.g. 95%). 3.  Calculate the standard error. 4.  Find the corresponding t-values. 5.  Use the formula to calculate the confidence interval. Example What it means to be confident 1 13 11/23/10 11 12 13 14 15 16 17 18 Example What it means to be confident •  For a 80% confidence interval, – if a series of confidence intervals were constructed, 80% of the intervals will contain the population mean – 20% of all intervals will be false. What it means to be confident •  Typically, we only choose one confidence interval. •  For a 80% confidence interval, the one interval that we actually computed has a 20% chance of not containing the population mean. Sample size and confidence intervals Interval estimates Example Precision vs. Confidence Sampling distribution of the mean 2 ...
View Full Document

{[ snackBarMessage ]}

### Page1 / 2

13_(Ch12)_Estimation_Outline - 1 2 3 4 5 6 7 8 9 10 11 12...

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

View Full Document
Ask a homework question - tutors are online