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charle [14.2K]
3 years ago
13

The population of scores on the SAT forms a normal distribution with μ =500 and σ = 100. If you take a random sample of n =100 w

hat is the probability that the sample mean will be greater than M = 520
Mathematics
1 answer:
Hitman42 [59]3 years ago
5 0
P(M > 520) = 1 - P(M < 520) = 1 - P(z < (520 - 500)/(100/sqrt(100))) = 1 - P(z < (20/(100/10))) = 1 - P(z < 20/10) = 1 - P(z < 2) = 1 - 0.97725 = 0.02275
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Write the equation of a circle given the center (-4, 4) and raduis r = 5.
Len [333]

Answer:

A) (x+4)^2+(y-4)^2=25

Step-by-step explanation:

The equation of a circle is (x-h)^2+(y-k)^2=r^2 where (h,k) is the center and r is the radius. If (h,k)\rightarrow(-4,4) and r=5, then:

(x-h)^2+(y-k)^2=r^2\\\\(x-(-4))^2+(y-4)^2=5^2\\\\(x+4)^2+(y-4)^2=25

Therefore, the equation of the circle is (x+4)^2+(y-4)^2=25

6 0
3 years ago
Two quadratic functions are shown.
slava [35]

Answer:

Option (1) is the correct option.

Step-by-step explanation:

Function 1,

f(x) = 4x² + 8x + 1

     = 4(x² + 2x) + 1

     = 4(x² + 2x + 1 - 1) + 1

     = 4(x² + 2x + 1) - 4 + 1

f(x) = 4(x + 1)² - 3

This graph opens up with the vertex or minimum point at (-1, -3)

So, the minimum value of the function is (-3) at x = -1.

Function (2)

From the given table minimum value of the function is 0 at x = -1 or minimum point as (-1, 0)

Therefore, Function 1 has the least minimum value and its coordinates are (-1, -3)

Option (1) is the correct option.

7 0
3 years ago
USA Today reports that about 25% of all prison parolees become repeat offenders. Alice is a social worker whose job is to counse
pychu [463]

Answer:

a) P(X=0)=(4C0)(0.75)^0 (1-0.75)^{4-0}=0.0039  

P(X=1)=(4C1)(0.75)^1 (1-0.75)^{4-1}=0.0469  

P(X=2)=(4C2)(0.75)^2 (1-0.75)^{4-2}=0.211  

P(X=3)=(4C3)(0.75)^2 (1-0.75)^{4-3}=0.422  

P(X=4)=(4C4)(0.75)^2 (1-0.75)^{4-4}=0.316

b) E(X) = np = 4*0.75=3

c) Sd(X) =\sqrt{np(1-p)}=\sqrt{4*0.75*(1-0.75)}=0.866

d) P(X \geq 3) \geq 0.98

And the dsitribution that satisfy this is X\sim Binom(n=9,p=0.75

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Let X the random variable of interest, on this case we now that:

X \sim Binom(n=4, p=1-0.25=0.75)

The probability mass function for the Binomial distribution is given as:

P(X)=(nCx)(p)^x (1-p)^{n-x}

Where (nCx) means combinatory and it's given by this formula:

nCx=\frac{n!}{(n-x)! x!}

Part a

P(X=0)=(4C0)(0.75)^0 (1-0.75)^{4-0}=0.0039  

P(X=1)=(4C1)(0.75)^1 (1-0.75)^{4-1}=0.0469  

P(X=2)=(4C2)(0.75)^2 (1-0.75)^{4-2}=0.211  

P(X=3)=(4C3)(0.75)^2 (1-0.75)^{4-3}=0.422  

P(X=4)=(4C4)(0.75)^2 (1-0.75)^{4-4}=0.316

Part b

The expected value is givn by:

E(X) = np = 4*0.75=3

Part c

For the standard deviation we have this:

Sd(X) =\sqrt{np(1-p)}=\sqrt{4*0.75*(1-0.75)}=0.866

Part d

For this case the sample size needs to be higher or equal to 9. Since we need a value such that:

P(X \geq 3) \geq 0.98

And the dsitribution that satisfy this is X\sim Binom(n=9,p=0.75

We can verify this using the following code:

"=1-BINOM.DIST(3,9,0.75,TRUE)" and we got 0.99 and the condition is satisfied.

4 0
3 years ago
In January Caleb could do 12 pushups. In May Caleb could do 15 pushups. By what percent did he increase the number of pushups he
Nimfa-mama [501]

Answer:

by 3% percent

Step-by-step explanation:

i hope this helps ._.

5 0
2 years ago
Read 2 more answers
A pair of shoes usually sell for $63. If the shoes are 40% off, and a sale tax of 7% is allied to discount cost, what is the tot
faust18 [17]

Answer:

$42

Step-by-step explanation:

40% of $63 is $25.2

$63 - $25.2 = $37.8

How much your paying without tax 37.8

7% of $63 is $4.41.

$37.8 + $4.41 = $42.21

Rounded 42.21 = 42

Im not 100% sure about the rounding but I hope this helps!

6 0
3 years ago
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