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spinal shock
Forum Newbie Topics: 23 Posts: 241 
the IQ scores are obtained for a sample of 100 patients diagnosec with various types of schizophrenia who completed a standard IQ test battery. an additional 20 patients had to be dropped from the sample because they lacked the functional capacity to complete two or more portions of the test. four other patients refused to take test battery when offered the opportunity. results for the patients who completed the test battery gave an average IQ of 110 and a standard deviation of 20. using this info compute 95% confidence interval for this estimate of the mean a.70 to 130 b.70 to 150 c.85 to 115 d.90 to 130 e.105 to 115 f.106 to 114 i know its tough Q but i need to know it  
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sigh
Forum Junior Topics: 73 Posts: 1743 
The question is not easy for sure but I think it was well explained in Kaplan Qbank... what part you did not get?  
skamran
Forum Senior Topics: 14 Posts: 124 
b 70 to 150  
spinal shock
Forum Newbie Topics: 23 Posts: 241 
i only got the q, ill be grateful if you sent me the answer,plz  
sigh
Forum Junior Topics: 73 Posts: 1743 
Memorize: Mean +/ Z (S / square root of N) The mean is 110. The standart deviation S is 20. The sample size is 100. Z is just a number to memorize, it is 1.96 or 2.0 for calculation. So, we use Z=2 to calculate 95%cofidence interval. Put all numbers together: 110+/ 2(20/square root of 100) = 110+/ 4 = 106 to 114 F is correct P.S. you are not suppose to pay attention to numbers of people who did not finish the test for this tpe of question.  
spinal shock
Forum Newbie Topics: 23 Posts: 241 
thanks sigh you are so great  
Ig F
Forum Guru Topics: 3 Posts: 500 
use these values in the formula of confidence interval..... CI=mean+/Z score(SD/sq. root of N) Fis the correct answer....  
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