# Using Confidence Intervals for Hypothesis Tests

In this video, we continue our discussion on hypothesis tests with means of samples and explore the use of confidence intervals (CI) as an alternative to point estimates for an unknown population mean

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## About Using Confidence Intervals for Hypothesis Tests

PowerPoint presentation about 'Using Confidence Intervals for Hypothesis Tests'. This presentation describes the topic on In this video, we continue our discussion on hypothesis tests with means of samples and explore the use of confidence intervals (CI) as an alternative to point estimates for an unknown population mean. The key topics included in this slideshow are . Download this presentation absolutely free.

## Presentation Transcript

Slide1Ch 5: Hypothesis Tests WithMeans of Samples Pt 3:  Sept. 17, 2013

Slide2Confidence Intervals• CI is alternative to a point estimate for an unknown population mean – Last week, we discussed how to calculate 95% and 99% CI (both 1 and 2-tailed). – Now, how to use these CI for hypothesis testing • As an alternative to significance testing (the 5-step hypothesis testing procedure covered earlier in Ch 5) • …a new example / review of how to calculate a CI…

Slide3Using CI for hypothesis testing• Null & Research hypothesis developed same as for point estimate hyp test – Gather information needed :  M (sample mean), N (sample size),  μ  (population mean), and  σ  (population SD) – Find  σ M   (standard dev of the distribution of means) – Find relevant z score(s) – based on 95 or 99% and 1-or 2- tailed test – Use z-to-x conversion formula for both positive and negative z values found in previous step (x = z( σ M ) + M) – This gives you the range of scores for the CI

Slide4If the CI  does not  contain the mean from the null hyp ( which is  μ ) ,      Reject Null. • Note that the CI is built around M, so you don’t want to use M to make this comparison with the CI, but use  μ  (population comparison mean) • So if  μ  is  outside  the interval, you conclude M and μ  differ – Just like ‘rejecting the null’    we conclude the two means differ significantly

Slide5Point Estimate Hypothesis Testing (review)• Is our decision based on the CI the same as we would make from the point estimate hypothesis test? – 1) Null & Research – 2 &3) Comparison Dist & Cutoff scores – 4) Find sample’s z score • Z = (M - µ) /  σ M – 5) Reject or fail to reject?