The Lifetime of a Light Bulb Is Exponentially Distributed with

question 98

Short Answer

The lifetime of a light bulb is exponentially distributed with  = 0.001.
a. What are the mean and standard deviation of the light bulb's lifetime?
b. Find the probability that a light bulb will last between 110 and 150 hours.
c. Find the probability that a light bulb will last for more than 125 hours.

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Definitions:

Trial Balance

A bookkeeping worksheet in which the balances of all ledgers are compiled into debit and credit account column totals that are equal.

Uncollectable Account

A debt or receivable that is considered to be uncollectible from a debtor, often because it is overdue or the debtor is unable to pay.

Collection Agency

An enterprise that seeks to collect payments from individuals or businesses on outstanding debts.

Pegboard System

A bookkeeping system that uses a lightweight board with pegs on which forms can be stacked, allowing each transaction to be entered and recorded on four different bookkeeping forms at once; also called the one-write system.