Answer:
A(BC) = (ABC. AI = JA = A
Answer:
What was this for ?
Step-by-step explanation:
Answer: 7
Step-by-step explanation:
Answer:
Number of families that should be surveyed if one wants to be 90% sure of being able to estimate the true mean PSLT within 0.5 is at least 43.
Step-by-step explanation:
We are given that one wants to estimate the mean PSLT for the population of all families in New York City with gross incomes in the range $35.000 to $40.000.
If sigma equals 2.0, we have to find that how many families should be surveyed if one wants to be 90% sure of being able to estimate the true mean PSLT within 0.5.
Here, we will use the concept of Margin of error as the statement "true mean PSLT within 0.5" represents the margin of error we want.
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<u>SO, Margin of error formula is given by;</u>
Margin of error =
where,
= significance level = 10%
= standard deviation = 2.0
n = number of families
Now, in the z table the critical value of x at 5% (
) level of significance is 1.645.
SO, Margin of error =
0.5 =

n =
= 43.3 ≈ 43
Therefore, number of families that should be surveyed if one wants to be 90% sure of being able to estimate the true mean PSLT within 0.5 is at least 43.
Answer:
The length of the rectangle 'l' = 20
The width of the rectangle 'w' = 14
Step-by-step explanation:
<u>Explanation</u>:-
Let 'x' be the width
Given data the length of a rectangular patio is 8 feet less than twice its width
2x-8 = length
The area of rectangle = length X width
Given area of rectangle = 280 square feet
x(2x-8) = 280
2(x)(x-4) =280
x(x-4) =140
x^2 -4x -140=0
x^2-14x+10x-140=0
x(x-14)+10(x-14)=0
(x+10)(x-14) =0
x = -10 and x = 14
we can choose only x =14
The width of the rectangle 14
The length of the rectangle 2x-8 = 2(14)-8 = 28 -8 =20
The length of the rectangle 'l' = 20
The width of the rectangle 'w' = 14