Answer:
Lowest Cost is for Drum set, when compared to others instruments of same type.
Highest cost is for Guitar,when compared to others instruments of same type.
Order:
Guitar>Piano>Drum Set
Step-by-step explanation:
Consider the normal distribution for all cases.
Formula we are going to use is:
[tex]z=\frac{\bar x-\mu}{\sigma}[/tex]
where:
[tex]\bar x[/tex] is the purchasing cost
[tex]\mu[/tex] is the mean
[tex]\sigma[/tex] is the standard deviation
For Piano:
[tex]z=\frac{3000-4000}{2500}\\ z=-0.4[/tex]
For Guitar:
[tex]z=\frac{550-500}{200}\\ z=0.25[/tex]
For Drum Set:
[tex]z=\frac{600-700}{100}\\ z=-1[/tex]
Lowest Cost is for Drum set, when compared to others instruments of same type.
Highest cost is for Guitar,when compared to others instruments of same type.
Order:
Guitar>Piano>Drum Set