The Reliability of Two Types of Machines Used in the Same

question 96

Essay

The reliability of two types of machines used in the same manufacturing process is to be tested. The first machine failed to operate correctly in 90 out of 300 trials while the second type failed to operate correctly in 50 out of 250 trials.
a.Give a point estimate for the difference between the population proportions of these machines.
b.Calculate the pooled estimate of the population proportion.
c.Carry out a hypothesis test to check whether there is a statistically significant difference in the reliability for the two types of machines using a .10 level of significance.

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Definitions:

Petty Cash

A small amount of cash on hand used for minor, incidental expenses of a business to avoid writing checks.

Cash Over and Short

An accounting line item that indicates the discrepancies between the amount of cash in the register and the amount of cash according to the accounting records.

Journal Entry

A record of financial transactions in the accounting system, showing accounts affected, amounts, and whether those accounts are debited or credited.

Petty Cash Account

A modest sum of money maintained readily available for covering various minor outlays instantly.