9514 1404 393
Answer:
[-4,3]
Step-by-step explanation:
The domain is the left-right (horizontal) extent of the function. The dots at the end of the continuous line are solid, so the brackets on the interval are square brackets.
The left dot is at x=-4; the right dot is at x=3, so the domain is ...
[-4,3]
Answer:
If the warranty limits are at 41.12 months, only 10 percent of the HDTVs need repairs at the manufacturer's expense.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by
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 problem, we have that:
For a new HDTV the mean number of months until repairs are needed is 36.84 with a standard deviation of 3.34 months. This means that .
Where should the warranty limits be set so that only 10 percent of the HDTVs need repairs at the manufacturer's expense?
This is the value of X when Z has a pvalue of 0.90.
Looking at the z-table, we get that this is between and
, so we use
.
If the warranty limits are at 41.12 months, only 10 percent of the HDTVs need repairs at the manufacturer's expense.