100 POINTS PLEASEEEES HELP ASAP DUE TONIGHT.
2 answers:
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Answer:
47.54% probability that more than 20 households but fewer than 35 households receive a retirement income
Step-by-step explanation:
We use the binomial aproxiation to the normal to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
Can be approximated to a normal distribution, using the expected value and the standard deviation.
The expected value of the binomial distribution is:
The standard deviation of the binomial distribution is:
Normal probability distribution
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.
When we are approximating a binomial distribution to a normal one, we have that ,
.
In this problem, we have that:
. So
In a random sample of 120 households, what is the probability that more than 20 households but fewer than 35 households receive a retirement income?
We are working with discrete values, so this is the pvalue of Z when X = 35-1 = 34 subtracted by the pvalue of Z when X = 20 + 1 = 21.
X = 34
has a pvalue of 0.9993
X = 21
has a pvalue of 0.5239
0.9993 - 0.5239 = 0.4754
47.54% probability that more than 20 households but fewer than 35 households receive a retirement income
Answer:
D. 220.16 Square feet
Step-by-step explanation: The shaded area is the space in the square not filled by the circle. So we need to find the area of the circle. The formula for area of a circle is . So we fill in this equation with the information we already know:
Simplify the exponents
Multiply
So now we know the area of the circle we have to find the area of the square because the circle is inside the square. It is a simple which is 1,024. Since we are looking for the shaded area we will subtract the area of the circle from the area of the square because the circle is not shaded.
1024-803.94= 220.16 square feet
If both triangles are similar the ratio of sides will be same