Confidence intervals

May 08, 2012

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These intervals are for distributions where the standard deviation of the population is known.. Confidence intervals for the population mean. From previous work on the Central Limit Theorem we know that if a sample is taken from any type of statistical distribution then the sample will be distribu

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Confidence intervals

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1. Confidence intervals www.ibmaths.com

CONFIDENCE INTERVALS

CONFIDENCE INTERVALS. DR.S.SHAFFI AHAMED ASST. PROFESSOR DEPT. OF F & CM. BACKGROUND AND NEED OF CI. ---Statistical analysis of medical studies is based on the key idea that, we make observations on a sample of subjects from which the sample is drawn.

856 views • 41 slides

Confidence Intervals

Statistical Inference. Statistical InferenceStatistical Inference is a procedure whereby, on the basis of observed data in a particular sample, we generalize and draw conclusions about the population from which the sample is drawn. Two general methods:. Statistical Inference. 1.Estimation of unkno

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Confidence Intervals

Confidence Intervals. Objectives: Students should know how to calculate a standard error, given a sample mean, standard deviation, and sample size Students should know what a confidence interval is, and its purpose

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Confidence Intervals

Confidence Intervals. Lecture XXI. Interval Estimation. As we discussed when we talked about continuous distribution functions, the probability of a specific number under a continuous distribution is zero.

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Confidence Intervals

Confidence Intervals. 10.2 page 625 a) There is a 95% probability (chance) that the interval from 107.8 to 116.2 contains µ. Incorrect. The probability is 1 or 0. We don’t know which!. 10.2 page 625 b) There is a 95% chance that the interval (107.8 ,116.2) contains x bar.

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Confidence Intervals

Confidence Intervals. Whenever we make a confidence interval we should follow these steps to be sure that we include all parts:. State the type of interval (our first intervals are Z -intervals). Meet assumptions (explain how each is met).

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Confidence Intervals

Confidence Intervals. General Mean (  ). Computation. First, edit and summarise the data. Obtain: sample size (n), sample mean (m) and sample standard deviation(sd). Note the indicated confidence level for the desired interval. Obtain the confidence coefficient (Z) via table look-up.

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Confidence intervals

Confidence intervals. Kristin Tolksdorf (based on previous EPIET material) 18 th EPIET /EUPHEM Introductory course 01 . 10 .201 2. Inferential statistics. Uses patterns in the sample data to draw inferences about the population represented, accounting for randomness .

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Confidence Intervals

Confidence Intervals. W&W, Chapter 8. Confidence Interval Review. For the mean: If  is known:  = M +/- Z  /2 *(  /  N) If  is unknown and N is large (  100):  = M +/- Z  /2 *(s/  N) If  is unknown and N is small (< 100):  = M +/- t  /2 *(s/  N).

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Confidence Intervals

Clinical Trials in 20 Hours. Confidence Intervals. Elizabeth S. Garrett esg@jhu.edu Oncology Biostatistics March 27, 2002. What is a “confidence interval”?. It is an interval that tells the precision with which we have estimated a sample statistic. Examples:

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Confidence Intervals

Confidence Intervals. Confidence Interval : An interval of values computed from the sample, that is almost sure to cover the true population value. We make confidence intervals using values computed from the sample, not the known values from the population

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Confidence Intervals

Confidence Intervals. Rate your confidence 0 - 100. Name my age within 10 years? within 5 years? within 1 year? Shooting a basketball at a wading pool, will make basket? Shooting the ball at a large trash can, will make basket? Shooting the ball at a carnival, will make basket?.

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Confidence Intervals

Confidence Intervals. This chapter presents the beginning of inferential statistics. We introduce methods for estimating values of these important population parameters: proportions, means, and variances.

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Confidence Intervals

Confidence Intervals. Chapter 10. Rate your confidence 0 - 100. Name my age within 10 years? within 5 years? within 1 year? Shooting a basketball at a wading pool, will make basket? Shooting the ball at a large trash can, will make basket?

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Confidence Intervals

Confidence Intervals. For a Sample Mean. Rate your confidence 0 - 100. Name my age within 10 years? within 5 years? within 1 year? Shooting a basketball at a wading pool, will make basket? Shooting the ball at a large trash can, will make basket?

548 views • 36 slides

CONFIDENCE INTERVALS

CONFIDENCE INTERVALS. point estimate : estimate exact value precise likely to be wrong interval estimate : range of values less precise less likely to be wrong. What a Confidence Interval Tells You. 1. Range of values 2. Level of confidence No hypothesis is directly tested.

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Confidence Intervals

Confidence Intervals. Confidence Intervals. Confidence Intervals. Examples: Confidence Intervals. 1. Among various ethnic groups, the standard deviation of heights is known to be approximately 3 inches. We wish to construct a 95% confidence interval for

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Confidence Intervals

Confidence Intervals. Chapter 10 and 11. Rate your confidence 0 - 100. Name my age within 10 years? within 5 years? within 1 year? Shooting a basketball at a wading pool, will make basket? Shooting the ball at a large trash can, will make basket?

555 views • 37 slides

Confidence Intervals

Confidence Intervals. Nancy D. Barker, M.S. Statistical Inference. Statistical Inference. Statistical Inference. Statistical Inference. Statistical Inference. Hypothesis Testing Is there evidence that the population parameter, e.g., RR , OR , IDR is different from the null value?

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