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:
1/5
Step-by-step explanation:
Range as a measure of central tendency is the difference between the highest value and the lowest value in a given set of data.
Given the samples 0,1,3,4,7
Total number of samples is 5
The range is gotten by taking the difference of 2 samplesout of 5samples and this can be done in 5C2 ways.
5C2 = 5!/(5-2)!2!
= 5!/3!2!
= 5×4×3!/3!×2
= 10ways
The total outcome is therefore 10
To get the probability that the range is 4, we need to get the required outcome of getting range of 4 and this can only occur twice
The range can be gotten by taking the difference between 7 and 3, it can also be gotten by taking the difference between 4 and 0. Both differences will give us a total of 4
The expected outcome is therefore 2
the probability that the range of the sample is 4 = expected outcome/total outcome
= 2/10
= 1/5
Answer:
x = 1 + sqrt(89) or x = 1 - sqrt(89)
Step-by-step explanation:
Solve for x:
(x - 9) (x + 7) = 25
Expand out terms of the left hand side:
x^2 - 2 x - 63 = 25
Add 63 to both sides:
x^2 - 2 x = 88
Add 1 to both sides:
x^2 - 2 x + 1 = 89
Write the left hand side as a square:
(x - 1)^2 = 89
Take the square root of both sides:
x - 1 = sqrt(89) or x - 1 = -sqrt(89)
Add 1 to both sides:
x = 1 + sqrt(89) or x - 1 = -sqrt(89)
Add 1 to both sides:
Answer: x = 1 + sqrt(89) or x = 1 - sqrt(89)
Answer:
The answer should be x ≤ 5
6:8 6 peaches 8 plums. If you doubled the fruit it would be 12:16
