February 27, 2017

Homework Help: statistics

Posted by looking for someone to varify my work please on Sunday, March 28, 2010 at 9:35am.

Section 5.3: Normal Distributions: Finding Values

Answer the questions about the specified normal distribution.

Q1: The lifetime of ZZZ batteries are normally distributed with a mean of 265 hours and a standard deviation ó of 10 hours. Find the number of hours that represent the the 25th percentile.

x = µ + zó
= 265 + -0.608 (10)
= 271.08

Q2: Scores on an English placement test are normally distributed with a mean of 36 and standard deviation ó of 6.5. Find the score that marks the top 10%.

x = µ + zó
= 36 + -1.208 (6.5)
= 28.15

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