hw4 - 25.3, and the 95% confidence interval is (19.6,...

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Homework 4 13 points You can use SPSS or the calculation tool on IntroStats to obtain any information (mean, SD, etc.) you may need. However, please attach any output you obtain from SPSS or write down any values you calculate from IntroStats to get full credit. Problems from Howell : Ch 12: 16; Ch 14: 12 (2 points each) Problems from Williams (Introstats.net): Ch 9: 1, 2, 4 (2 points each) You are interested in the level of depression in long-time smokers. You randomly selected a sample of 12 people who have smoked at least a pack every day for the last 10 years, and administered the Beck Depression Inventory. The mean of your sample is
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Unformatted text preview: 25.3, and the 95% confidence interval is (19.6, 31.0). 1. The cut-off point used by clinical psychologists to indicate a moderate level of depression is 20. Based on the 95% confidence interval, do you have evidence to suggest that long-term smokers show a moderately elevated level of depression? How can you tell? (1 point) 2. If you increased the confidence level from 95% to 99%, what would happen to the confidence interval? Why? (1 point) 3. If you increased the sample size and the mean and sample standard deviation remained the same, what would happen to the 95% confidence interval? Why? (1 point)...
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This note was uploaded on 07/17/2008 for the course PHYS 321 taught by Professor Zandt during the Spring '05 term at Ohio State.

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