Respuesta :
Assuming the costs are normally distributed, then Z = (X-mu)/sigma
For piano Z= (3000-4000)/2500 = -0.4
For guitar Z= (550-500)/200 = 0.25
For drums set Z= (600-700)/100 = -1
Drums set < Piano < Guitar
Drums cost is lowest when compared to the instruments of same type .
Guitar cost is highest when compared to the instruments of same type.
A z-score can be placed on a normal distribution curve. By using the z-score statistical tool we can analyze the lowest cost and highest cost a given in case the mean and standard deviation of a normal distribution is given.
What is a Z-score?
Z-score (also called standard points) gives you an idea of how far from the mean the data point is. But technically it is a measure of how many standard deviations are below or above the population means the raw score.
- A z-score of 1 is 1 standard deviation above the mean.
- A z- score of 2 is 2 standard deviations above the mean.
- A z-score of -1.8 is -1.8 standard deviations below the mean.
As per the given information, we need to calculate the z-score value, which is as follows:
[tex]\rm\,Z= \frac{X(Value \,Given) - Mean}{Sigma\,(Standard\,Deviation)}[/tex]
After putting the values,
[tex]\rm\, Z= \frac{X(Value \,Given) - Mean}{Sigma\,(Standard\,Deviation)} \\\\For\,piano, Z = \frac{X - Mean}{Sigma} \\\\Z = \frac{3,000 - 4,000 }{2,500} \\\\Z = - 0.4\\\\For\,Guitar, Z =\frac{X - Mean}{Sigma} \\\\Z =\frac{550- 500}{200} \\\\Z = 0.25\\\\For\,Drums\,Set, Z = \rm\,\dfrac{\rm\,X - Mean}{\rm\,Sigma}\\Z = \rm\,\dfrac{\rm\,600 - 700}{\rm\,100}\\\\Z = -1[/tex]
Therefore, Drum set cost is the lowest among others, -1 standard deviations below the mean whereas Guitar has the highest cost, 1 standard deviation above the mean.
To learn more about Z-score, refer to the link:
https://brainly.com/question/25638875