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Question 1191287: The time taken for a student to complete an exam is normally distributed with a mean of 40 minutes and a standard deviation of 5.5 minutes.
A student is randomly selected. What is the probability that the student completes the task in less than 48 minutes?
Answer by ikleyn(52782)   (Show Source):
You can put this solution on YOUR website! .
The time taken for a student to complete an exam is normally distributed with a mean
of 40 minutes and a standard deviation of 5.5 minutes.
A student is randomly selected. What is the probability that the student completes
the task in less than 48 minutes?
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The normal distribution curve is a bell shaped curve.
This question is to determine the area under the normal distribution curve
below (or to the left) of the given score.
It can be done in different ways:
- manually, or
- using online calculators, or
- using your pocket calculator.
MANUALLY
To do the job manually, use this Table representing AREA to the LEFT of the Z-score
https://www.math.arizona.edu/~rsims/ma464/standardnormaltable.pdf
On how to do it, see this Internet text source
http://statisticshelper.com/how-to-use-the-z-table
USING ONLINE CALCULATOR
To do the job using an online (free of charge) calculator, go to this web-site
https://onlinestatbook.com/2/calculators/normal_dist.html
Input the given parameters into an appropriate window of the calculator and get the answer
to your question.
The calculator has perfect description and design, as well as clear visual interface, which prevents you of making errors.
So EVERY person, even beginner, may work with it on his or her own, even having minimum knowledge on the subject.
USING YOUR POCKET CALCULATOR
On how to use it, see a text description in THIS Internet source / site
https://mathbits.com/MathBits/TISection/Statistics2/normaldistribution.htm
Or see these Youtube video-lessons
https://www.youtube.com/watch?v=bVdQ7OzGvU0 (for Casio fx-991 MS)
https://www.youtube.com/watch?v=yYpMkgB20C4 (for TI-83 or TI-84 calculators)
I recommend you to play with the online calculator first.
If you are unfamiliar with the subject, playing with the online calculator will help you a lot !
After learning it, you will be able to solve this problem (and thousand other similar and different problems) ON YOUR OWN,
without asking for help from outside.
Happy learning ( ! )
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