Mrs. Babin put a border around a 5-foot by 6-foot rectangular bulletin board. How
2 answers:
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Answer:
0.64%.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score 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 p-value, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Mean of 75 grams and a standard deviation of 22 grams.
This means that
Sample of 144:
This means that
More than 80 or less than 70:
Both are the same distance from the mean, so we find one probability and multiply by 2.
The probability that it is less than 70 is the pvalue of Z when X = 70. So
By the Central Limit Theorem
has a pvalue of 0.0032
2*0.0032 = 0.0064.
0.0064*100% = 0.64%
The probability is 0.64%.
Answer:
The three numbers are 7 8 and 9
Step-by-step explanation:
Givens
- Let the first number be n - 1
- Let the second number be n
- Let the third number = n + 1
Equation
(n - 1)(n)(n + 1) - (n-1 + n + n+1) = 480
Solution
Multiply (n - 1) and (n + 1) = (n - 1)*(n + 1) = n^2 - 1
Multiply the second integer by the result of the first and third: n (n^2 - 1)
Add the three integers together: (x - 1) + (n - 1) + n = 3n Combine these 2 steps
n(n^2 - 1) - 3n = 480 Remove the brackets
n^3 - n - 3n = 480
n^3 - 4n = 480
n^3 - 4n - 480 = 0
Graph
The graph shows that the intercept point is n =8. This is the only way I can see to solve this cubic. There are no other real roots.
Answer
n - 1 = 7
n = 8
n + 1 = 9
Check
Product 7*8*9 = 504
Sum = 7 + 8 + 9 = 24
504 - 24 = 480 Which checks.
