Practice quiz 8 and soln - Prequiz 8 1-2 We are interested...

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Prequiz 8 1.2 We are interested in estimating the mean score on the test, we sample n=36 individuals and compute an average of 80.1 and a sample estimate of variance equal to 1.44 i.e., n=36, x = 80.1 and s 2 = 1.44 so s=1.2. ______1.Compute a point estimate of μ , the mean test score. _______2. Compute a point estimate of the standard error. 3-4. Suppose we know that the standard deviation of blood pressure measurements equals 10mm. 3. We can predict that 98% of the averages based on a sample of n=16 measurements
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Unformatted text preview: will have maximum error less than what value? (Hint : Z 0.01 = 2.33) 4. Suppose we would like the maximum error of our average to be less than 2 mm. in 98% of our samples. Then what size sample do we need? ANSWERS 1. x = 80.1 2. 2 . 6 / 2 . 1 / = = n s 3. E= z α /2 σ / √ n = (2.33 x 10)/4 = 5.825 4. n = [z α /2 σ /E] 2 round up = [2.33 x 10/2] 2 =135.7 so rounding up n=136. We need a sample of 136 or more. 1...
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