a woodworker builds a picture frame that is 2 feet by 3 feet. find the perimeter of the frame in feet.
1 answer:
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Answer:
The average annual growth rate of a certain country's population for 1950, 1988, and 2010 are 2.398, 0.9985 and 0.2236 respectively.
Step-by-step explanation:
The given equation is
Where Y is the annual growth rate of a certain country's population and x is the number of years after 1900.
Difference between 1950 and 1900 is 50.
Put x=50 in the given equation.
Therefore the estimated average annual growth rate of the country's population for 1950 is 2.398.
Difference between 1988 and 1900 is 88.
Put x=88 in the given equation.
Therefore the estimated average annual growth rate of the country's population for 1988 is 0.9985.
Difference between 2010 and 1900 is 110.
Put x=110 in the given equation.
Therefore the estimated average annual growth rate of the country's population for 2010 is 0.2236.
Answer:
0.6214 = 62.14% probability that the sample proportion is between 0.26 and 0.38
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.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean and standard deviation
37% of the company's orders come from first-time customers.
This means that
A random sample of 225 orders will be used to estimate the proportion of first-time-customers.
This means that
Mean and standard deviation:
What is the probability that the sample proportion is between 0.26 and 0.38?
This is the pvalue of Z when X = 0.38 subtracted by the pvalue of Z when X = 0.26.
X = 0.38
By the Central Limit Theorem
has a pvalue of 0.6217
X = 0.26
has a pvalue of 0.0003
0.6217 - 0.0003 = 0.6214
0.6214 = 62.14% probability that the sample proportion is between 0.26 and 0.38
Answer:
20 ft long; 12 ft wide
Step-by-step explanation:
Let w = the width of the garden
Then l = w + 8
A = lw
A = (w + 8)w
=====
The sidewalk is 4 ft wide, so, for the big rectangle consisting of garden plus sidewalk:
Width = w +8
Length = w + 16
Area = (w + 8)(w + 16)
=====
The <em>difference</em> between the two areas is the area of the sidewalk (320 ft²).
(w + 8)(w + 16) - (w + 8)w = 320 Factor out w + 8
(w+ 8)(w + 16 – w) = 320 Combine like terms
(w+ 8) × 16 = 320 Divide each side by 16
w + 8 = 20 Subtract 8 from each side
w = 12 ft
l = 12 + 8
l = 20 ft
The garden is 20 ft long by 12 ft wide.
