The Life Expectancy of Computer Terminals Is Normally Distributed with a Mean

question 18

Short Answer

The life expectancy of computer terminals is normally distributed with a mean of 4 years and a standard deviation of 10 months.
a.What is the probability that a randomly selected terminal will last more than 5 years?
b.What percentage of terminals will last between 5 and 6 years?
c.What percentage of terminals will last less than 4 years?
d.What percentage of terminals will last between 2.5 and 4.5 years?
e.If the manufacturer guarantees the terminals for 3 years (and will replace them if they malfunction), what percentage of terminals will be replaced?

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Definitions:

Correlation Coefficient

A measure that determines the degree to which two variables' movements are associated, ranging from -1 to 1.

Friedman Test

A non-parametric test used to detect differences in treatments across multiple test attempts.

Randomized Block Experiment

An experimental design that groups subjects into blocks based on certain intrinsic characteristics before randomly assigning treatments within each block to account for variability.

Rejection Region

The range of values in a statistical test for which the null hypothesis is rejected.