Answer:
a. Assume that the population has a normal distribution.
b. The 90% confidence interval of the mean sale time for all homes in the neighborhood is between 219.31 days and 240.69 days.
Step-by-step explanation:
Question a:
We have to assume normality.
Question b:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
That is z with a pvalue of
, so Z = 1.645.
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 230 - 10.69 = 219.31 days.
The upper end of the interval is the sample mean added to M. So it is 230 + 10.69 = 240.69 days.
The 90% confidence interval of the mean sale time for all homes in the neighborhood is between 219.31 days and 240.69 days.
The answer is definitely 30 :) thanks for the points!
Answer:

Step-by-step explanation:





Answer:
81
Step-by-step explanation:
Let the digits that make up the number be a and b.
Given that the square root of the number is equal to the sum of the digits.
Then,
√(10a + b) = a + b
Also given that the square root of the number is less than the number obtained by interchanging the digits by 9, then
√(10a +b) + 9 = 10b + a
Since √(10a + b) = a + b, then
a + b + 9 = 10b + a
a - a + 9 = 10b - b
9b = 9
b = 1
since √(10a + b) = a + b
√(10a + 1) = a + 1
10a + 1= (a + 1)²
10a + 1 = a² + 2a + 1
a² + 2a - 10a + 1 - 1 = 0
a² - 8a = 0
a(a - 8) = 0
a = 0 or a = 8
Using a = 8 and b = 1,
the number 10a + b = 10(8) + 1 = 81.
Answer:
HI = GJ ( GIVEN) s
GH = IJ ( given) s
Gi = Gi ( common side) s
And boom
GHI = Gji ( mention above eq, being SSS)
S mean side