Google Answers Logo
View Question
Q: Statistics ( Answered,   0 Comments )
Subject: Statistics
Category: Business and Money > Accounting
Asked by: lola5-ga
List Price: $10.00
Posted: 25 Aug 2005 15:45 PDT
Expires: 24 Sep 2005 15:45 PDT
Question ID: 560536
A supervisor of White Industries is considering a new method of
assembling its cart product.  The present method requires 42.3
minutes, on the average, to assemble a cart. The mean assembly time
for a random sample of 24 carts, using the new method, was 40.6
minutes, with a standard deviation of 2.7 minutes.  Using the 0.05
level of significance, can we conclude that the assembly time using
the new method is faster?

Request for Question Clarification by scriptor-ga on 25 Aug 2005 15:59 PDT
Google Answers discourages and may remove questions that are homework
or exam assignments.

Subject: Re: Statistics
Answered By: omnivorous-ga on 26 Aug 2005 04:18 PDT
Lola5 ?

What we?re seeking here is the confidence interval with p = 0.05. 
Restated, it?s a 95% confidence that the same fall within the range. 
It's calculated as:

mean +/- T-value * SD
?Statements of probability and confidence intervals? (undated)

The small sample size here calls for the use of the Student?s
T-distribution, which narrows the range of values depending on the
sample size.  It's important to remember that the degrees of freedom
are one less than the sample size:

Statsoft Electronic Textbook
?Student?s T Table? (2003)

Thus at p < 0.05, the mean is 40.6 +/-  (1.713872) * 2.7 

So, anything in that range is statistically expected and we can?t
reject the hypothesis H0 (also called the null hypothesis) ? that this
new assembly technique is the same as the 42.3 minutes of the old
technique.  Only those values outside the range would support
hypothesis H1 ?  the alternate hypothesis --

Statistics Glossary
?Hypothesis Testing?

So, values between 40.6 +/- 4.63 minutes or in the range of 35.97 ?
45.23 are indistinguishable from our sample.  Of course 42.3 minutes
is well within that range, so we can?t conclude that we?re doing any

Google search strategy:
Probablility + ?confidence interval?
T distribution

Best regards,

There are no comments at this time.

Important Disclaimer: Answers and comments provided on Google Answers are general information, and are not intended to substitute for informed professional medical, psychiatric, psychological, tax, legal, investment, accounting, or other professional advice. Google does not endorse, and expressly disclaims liability for any product, manufacturer, distributor, service or service provider mentioned or any opinion expressed in answers or comments. Please read carefully the Google Answers Terms of Service.

If you feel that you have found inappropriate content, please let us know by emailing us at with the question ID listed above. Thank you.
Search Google Answers for
Google Answers  

Google Home - Answers FAQ - Terms of Service - Privacy Policy