Answer:
171 newspapers.
Step-by-step explanation:
Problems of normally distributed samples are 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:
How many newspapers should the newsstand operator order to ensure that he runs short on no more than 20% of days
The number of newspapers must be on the 100-20 = 80th percentile. So this value if X when Z has a pvalue of 0.8. So X when Z = 0.84.
So 171 newspapers.
Answer: in order to qualify, the time must be at least 15.93 minutes
Step-by-step explanation:
Let x be a random variable representing the average response times of fire departments to fire calls. Since it follows a normal distribution, we will determine the z score by applying the formula,
z = (x - µ)/σ
Where
x = sample mean
µ = population mean
σ = population standard deviation
From the information given,
µ = 12.8 minutes
σ = 3.7 minutes
in order to qualify for the special safety award, the probability value would be to the right of the z score corresponding to 80%
The z score corresponding to 80% on the normal distribution table is 0.845
Therefore,
0.845 = (x - 12.8)/3.7
0.845 × 3.7 = x - 12.8
3.13 = x - 12.8
x = 12.8 + 3.13 = 15.93
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The formula for the area of a square is the side squared, or multiplied together.
Basically, if the side length is x, the area is x*x or x^2.
We can use that to set up an equation.
x^2=121
x=square root of 121=11
Hope this helps!
Answer:
$65
Step-by-step explanation:
All 12 of the televisions have extended warranties so 12*15= 180
Then subtract 960-180= 780
Now divide 780/12 = $65
