Question

The graph illustrates a normal distribution for the prices paid for a particular model of HD television. The mean price paid is $1000 and the standard deviation is $100.

7008009001000110012001300Distribution of Prices

What is the approximate percentage of buyers who paid between $700 and $1000?
%

What is the approximate percentage of buyers who paid between $900 and $1000?
%

What is the approximate percentage of buyers who paid more than $1300?
%

What is the approximate percentage of buyers who paid between $900 and $1100?
%

What is the approximate percentage of buyers who paid more than $1200?
%

What is the approximate percentage of buyers who paid between $800 and $1000?

Answer 1

(a)			(b)			(c)
µ	1000		µ	1000		µ	1000
σ	100		σ	100		σ	100
x	1000		x	1000		x	1300
z = (x - µ)/σ	0		z = (x - µ)/σ	0		z = (x - µ)/σ	3
p-value	0.5000		p-value	0.5000		p-value	0.13%
x	700		x	900
z = (x - µ)/σ	-3		z = (x - µ)/σ	-1
p-value	0.0013		p-value	0.1587
Req.	49.87%		Req.	34.13%
(d)			(e)			(d)
µ	1000		µ	1000		µ	1000
σ	100		σ	100		σ	100
x	1100		x	1200		x	1000
z = (x - µ)/σ	1		z = (x - µ)/σ	2		z = (x - µ)/σ	0
p-value	0.8413		p-value	2.28%		p-value	0.5000
x	900					x	800
z = (x - µ)/σ	-1					z = (x - µ)/σ	-2
p-value	0.1587					p-value	0.0228
Req.	68.27%					Req.	47.72%

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