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dedylja [7]
3 years ago
8

Consider a normal distribution curve where 90-th percentile is at 20 and the 25-th percentile is at 10. use this information to

find the mean, μ , and the standard deviation, σ , of the distribution.

Mathematics
1 answer:
ivann1987 [24]3 years ago
5 0
The 25th percentile corresponds to z ≈ -0.67.
The 90th percentile corresponds to z ≈ 1.28.
So, you can write two equations in μ and σ as here:
.. μ -0.67σ = 10
.. μ +1.28σ = 20

The solution is
.. μ ≈ 13.45
.. σ ≈ 5.11

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3 years ago
Mr. rodriquez was on the telephone for 182 minutes. She called 7 friends to invite them to a luncheon. If she spoke to each frie
vitfil [10]
He spoke to each friends for 26 minutes

How I found out : how I found out is that all you have to do it get the total amount which in this question it is going to be 182. And you would need to dive 182 by 7 to find the unit rate (182/7) which is going to equal 26.which means he called each friend for 26 minutes
5 0
3 years ago
Read 2 more answers
In order to estimate the difference between the average hourly wages of employees of two branches of a department store, two ind
liberstina [14]

Answer:

Step-by-step explanation:

Hello!

You have two populations of interest and want to compare them. If you define the study variables as:

X₁: average hourly wages of an employee of the Downtown store.

n₁= 25

X[bar]₁= $9

S₁= $2

X₂: average hourly wages of an employee of the North Mall store.

n₂= 20

X[bar]₂= $8

S₂= $1

Both samples taken are independent, assuming that both populations are normal and that their population variances are equal I'll use the Student's-t statistic with a pooled sample variance to calculate the Confidence interval:

95% CI for μ₁ - μ₂

(X[bar]₁-X[bar]₂) ± t_{n_1+n_2-2; 1-\alpha /2} * (Sa*\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } )

Sa^2= \frac{(n_1-1)S_1^2+(n_2-1)S_2^2}{n_1+n_2-2}

Sa^2= \frac{24*4+19*1}{25+20-2}= 2.67

Sa= 1.64

t_{n_1-n_2-2;1-\alpha /2} = t_{43; 0.975} = 2.017

(9-8)±2.017*(1.64*\sqrt{\frac{1}{25} +\frac{1}{20} } )

[0.007636;1.9923]

I hope it helps!

6 0
3 years ago
Find the area of the polygon.
Anastaziya [24]

Answer:

to find the area of a polygon

formula: area = 1/2 x perimeter x apothem

Step-by-step explanation:

Here is what it means: Perimeter = the sum of the lengths of all the sides. Apothem = a segment that joins the polygon's center to the midpoint of any side that is perpendicular to that side.

5 0
3 years ago
The graph of a function is shown below. find the following, g(10), g(-3)
Rzqust [24]

Answer:

g(5x)=0

Step-by-step explanation:

Given that g(x)=4

From the graph when x=-2 then g(x)=4

Hence 5x=-10

Now from the graph

g(-10)=0

4 0
3 years ago
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