psyc 60 Z score worksheet 3 with nswers

# psyc 60 Z score worksheet 3 with nswers - Given a...

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Given a population with μ = 23 and σ = 5, 1. What percent of the data are lower than 25? 2. What value is exactly 40 percent of the data higher then? 3. What percent of the data falls between values of 28 and 34? 4. What proportion of data are lower than 15? 5. What value is the 80th percentile? 6. What value is above exactly 20 percent of the data?

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μ = 23 and σ = 5, 1. What percent of the data are lower than 25? Convert to z-value: z = (x- μ )/ σ = (25-23)/5 = .4 ? x: 23 25 z: 0 .4 Either: For z = .4 in column A, lookup the corresponding area from column C: .3446 1 - .3446 = .6554 (.6554)100=65.54% Or: For z = .4 in column A, lookup the corresponding area from column B: .1554 .5 + .1554= .6554 (.6554)100=65.54% 2. What value is exactly 40 percent of the data higher then? .40 x: 23 ? z: 0 ? For an area of .40 in column C, lookup corresponding z score in column A: ~.25. Convert z-score to data value, x = (z)(
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## This note was uploaded on 01/23/2011 for the course PSYC 60 taught by Professor Ard during the Fall '08 term at UCSD.

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psyc 60 Z score worksheet 3 with nswers - Given a...

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