Respuesta :
Answer:
A warranty of 6.185 years should be provided.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:
[tex]\mu = 8.2, \sigma = 1.3[/tex]
What warranty should be provided so that the company is replacing at most 6% of their blenders sold?
The warranty should be the 6th percentile, which is X when Z has a pvalue of 0.06. So X when Z = -1.55.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]-1.55 = \frac{X - 8.2}{1.3}[/tex]
[tex]X - 8.2 = -1.55*1.3[/tex]
[tex]X = 6.185[/tex]
A warranty of 6.185 years should be provided.
