A sample from a population with μ = 40 and σ = 8 has a mean of M = 36. If the sample mean corresponds to a z = –1.00, then how many scores are in the sample?

Answers

Answer 1

Answer:

There are 4 scores in the sample.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

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.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this question, we have that:

[tex]\mu = 40, \sigma = 8, X = 36, Z = -1, s = \frac{8}{\sqrt{n}}[/tex]

We want to find n. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]-1 = \frac{36 - 40}{\frac{8}{\sqrt{n}}}[/tex]

[tex]-4\sqrt{n} = -8[/tex]

[tex]4\sqrt{n} = 8[/tex]

Simplifying by 4

[tex]\sqrt{n} = 2[/tex]

[tex](\sqrt{n})^2 = 2^2[/tex]

[tex]n = 4[/tex]

There are 4 scores in the sample.


Related Questions

Help ASAP ASAP

Help asappp

Answers

Answer:

-3.9

Step-by-step explanation:

y/0.3 - 1.4= -14.4
•0.3. •0.3
y-1.4= -4.32
+1.4= +1.4
y= -2.92

b) A first-time house buyer can make 240 monthly payments of £675 to repay the mortgage. How many monthly payments are required if she can pay £600 per month?

Answers

she would need 270 payments

need help pleaseeee !!!

Answers

Answer:

A (0,8)

B (1,4)

C (2,2)

D (3,1)

please help me on this

Answers

9514 1404 393

Answer:

  10 ft

Step-by-step explanation:

The midsegment length is the average of the other two lengths.

  (QR +PS)/2 = TU

  QR +PS = 2×TU . . . . . . . . . . . . . . . multiply by 2

  QR = 2×TU -PS = 2(14 ft) -18 ft . . . subtract PS; substitute given values

  QR = 10 ft

HELP OR I EAT YOUR COOKIES (5TH GRADE MATH)
Lamont's empty backpack weighs 2 1/2 pounds. He puts 4 notebooks in it that each weigh 15 ounces. How many pounds does Lamont's backpack weigh now?

Answers

The answer is 6.252 pounds.

2 1/2 as a decimal is 2.5, and 15 ounces is equal to 0.938 pounds. Since there are 4 notebooks, you multiply 0.938 by 4, which is 3.752. Now, you just add 2.5+3.752=6.252

What the degrees measure for 5/9 of a circle

Answers

Answer:

200

Step-by-step explanation:

5*360/9=200

pencils cost 2 dollars each. Rulers cost 3 dollars each. Edith buys p pencils and r rulers. The total cost is T dollars. What is the formula for T in terms of p and r​

Answers

(2 x p) + (3x r ) = T that would be the equation

Please hurry! Will be choosing brainliest!
In the cone below, the radius is 6 meters and the height is 8 meters.
Find the volume of the cylinder pictured below. Use 3.14 for pi. Give your answer

Answers

Answer:

301.59

Step-by-step explanation:

301.59 yw have a good day

which pairs of expressions are equivalent to one another? Mark all that apply.
-10 - (-7) and -10 + (-7)
7 + (-16) and 16 - 7
11 - 5 and 11 + (-5)
7 - 13 and 13 - 7
-20 - (-45) and -20 + 45
9 + 8 and 9 - (-8

Answers

Answer:

11 - 5 and 11 + (-5)

-20 - (-45) and -20 + 45

9 + 8 and 9 - (-8

Step-by-step explanation:

Two negatives make a positive so -- and + are the same

What transformation rule would represent a shift of 3 units to the left 4 units down?
Group of answer choices

(x,y) –> (x – 4, y – 3)

(x,y) –> (x – 3, y – 4)

(x,y) –> (4x, 3y)

(x,y) –> (x + 3, y + 4)

Answers

Given:

Shift of 3 units to the left 4 units down.

To find:

The transformation rule.

Solution:

The rule of transformation is

[tex](x,y)\to (x+a,y+b)[/tex]          ...(i)

Here, a<0 if the figure shifts a units left and a>0 if the figure shifts a units right.

Similarly, b<0 if the figure shifts b units down and b>0 if the figure shifts b units up.

If a transformation represents shift of 3 units to the left 4 units down, then a=-3 and b=-4.

Putting a=-3 and b=-4 (i), we get

[tex](x,y)\to (x+(-3),y+(-4))[/tex]

[tex](x,y)\to (x-3,y-4)[/tex]

Therefore, the correct option is B.

Write down in figures the number forty one thousand and ninety six.

Answers

Answer:

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Step-by-step explanation:

Answer:

41,096

Hope it helps

Please mark me as the brainliest

Thank you

Round 1526.04 to the nearest tenths

Answers

1526.00

This is because the 4 is not atleast or greater than five, therefore it rounds down.

please help me its due later today

Answers

Answer:

y

___

2

1

-2

-1

in that order, hope this helps :)

Answer:

a) y=2

b) y=1

c) y= -1

d) y= -2

Step-by-step explanation:

Consider the function given below.

Answers

you have to put a picture of the problem

HELP PLSS I DONT WANNA FAIL

Answers

Answer: 1/2 and 3/6

Explanation: 1/2 is equal to 3/6 because if you divide both 3 and 6 by 2 it’s 1/2

Not sure about 4

For a cat that weighs 15 pounds, rank the following scale weights from least
accurate to most accurate.
15.10 pounds
13.9 pounds
16.2 pounds
15.01 pounds

Answers

Answer:

16.2 pounds (least accurate)

13.9 pounds (2nd least accurate)

15.10 pounds (2nd most accurate)

15.01 pounds (most accurate)

Step-by-step explanation:

I hope this helps :)

Answer:

16.2 pounds

13.9 pounds

15.10 pounds

15.01 pounds

Please help

Look at picture and match

Answers

Answer:

It is the same order

Step-by-step explanation:

A=1/2bh triangle

A=bh parallelogram

A=1/2(b1 + b2)h trapezium

Answer:

Step-by-step explanation:

A=1/2bh =triangle

A=bh= parallelogram.

A=1/2(b1-b2)h=trapezoid.

Substitute t = 3 and t = 6 to determine if the two expressions are equivalent. 3 (2 t + 5) 6 t + 15 Which statements are true? Select the three correct answers. The value of both expressions when t = 3 is 33. The value of both expressions when t = 3 is 23. The value of both expressions when t = 6 is 41. The value of both expressions when t = 6 is 51. The two expressions are equivalent. The two expressions are not equivalent.

Answers

Answer:

If t= 6

3 (2 x 6 + 5) 6 x 6 + 15

3 (12+5) 36 + 15

3 x 17 =51

= 51

The value of both expressio

Step-by-step explanation:

The value of both expressions when t=6 is 51

When t = 3

3(2 x 3 + 5) 6 x 3 + 15

3 (6 +5) 18 + 15

3 x 11 =33

= 33

The value of both expressions when t= 3 is 33

Answer:

A. The value of both expressions when t=3 is 33

D. The value of both expressions when t = 6 is 51.

E. The two expressions are equivalent.

Step-by-step explanation:

Solve for x:
X х+ 9 = 5x — 11

Answers

Answer:

5

Step-by-step explanation:

   x+9-(5*x-11)=0

  -4x + 20  =   -4 • (x - 5)

  -4   =  0

x-5 = 0

Add  5  to both sides of the equation :

                     x = 5

2. The sides of a triangle are in the ratio 3:7:10 and the perimeter is 80 inches.
What are the lengths of the sides of the triangle?

Can anyone help please ?​

Answers

Step-by-step explanation:

3+7+10=20

80/20=4

1 ratio =4

3(4) : 7(4) : 10(4)

= 12 : 28 : 40

Please solve
(2x^2 +x+4) (x+7) = 6x^3+29x^2+47x+28
with explanation
ASAP!!!
On a time crunch!!!!!

Answers

Answer: x = 0

Step-by-step explanation:

Subtract 6x^3+29x^2+47x+28 from both sides:

(2^2 + x + 4) (x - 7) - 6x^3+29x^2+47x+28

(6x^3+29x^2+47x+28)-6x^3+29x^2+47x+28

= -4x^3 - 14x^2 - 36x = 0

Now factor the left side:

-4x^3 - 14x^2 - 36x = 0

(-2x) (2x^2 + 7x + 18) = 0

Now set the factors equal to 0

-2x = 0 or 2x^2 + 7x + 18 = 0

x = 0

what is the answer? help me

Answers

The answer that I would choose would be C.

What is the answer to the angle BD?

Answers

straight angle. this is easyyy

Please help, I have been stuck for a while, it is about trig.

Answers

Answer: x=28, y=14

Step-by-step explanation:

This article gives the formula for finding the sides of a 30-60-90 triangle. https://blog.collegevine.com/complete-guide-30-60-90-triangle/

The gist of it is that the hypotenuse is 1, the short side is 2, and the long side is root3. Since there was a 14 with the root3, I multiplied the 1 and 2 for the other sides by 14 to get 28 and 14.

The table shows the number of words per minute Josylyn can type. What is the missing value?

Answers

Answer:

52

Step-by-step explanation:

First, we want to see how we get from 104 to 156.

Looks like we add 52 to get the next.

104 + 52 = 156

156 + 52 = 208

Logically if we want to go back, we simply subtract 52.

104 - 52 = 52

Answer:

52

Step-by-step explanation:

What is the approximate area of the shaded sector in the circle below?

Answers

Answer: I believe the answer is 51 inches squared

Step-by-step explanation:

The number of dogs at the shelter is a two digit, odd number. It is more than 80. The tens digit is less than the ones digit. The sum of the digits is 17. How many dogs are at the shelter?

Answers

Answer:

89

Step-by-step explanation: the sum of both numbers are 17/ 9+8=17.

89 is greater than 80

Answer:

89

Step-by-step explanation:

89 is greater than 80

8 is less than 9

8 + 9 = 17

It meets all the requirements

ill mark brainlistn plsshelp

Answers

Answer:

the answer is 18 because you have to multiply 6 times 3 and get 18

Which expression represents the product of x^3+2x-1 andx^4-x^3+3

Answers

Answer: x^4 + 2x + 2

Step-by-step explanation:

I just took the test. :)

Answer: x^4 + 2x + 2

Step-by-step explanation:

Big brain

Suppose that you live in a community that has 125,000 households. Among these households, 50,000 have traditional landline telephones while the remaining 75,000 only use cellular and / or VOIP telephones. We are going to select 100 households from your community at random without replacement. The first household selected does not have a traditional landline telephone. What is the probability that the second household selected will have a traditional landline telephone

Answers

Answer:

0.4 = 40% probability that the second household selected will have a traditional landline telephone

Step-by-step explanation:

A probability is given by the number of desired outcomes divided by the number of total outcomes.

We have that:

125,000 households

50,000 have traditional landlines telephones.

The first household selected does not have a traditional landline telephone.

Now we have 125000 - 1 = 124,999 households, and 50,000 have traditional landlines telephones.

What is the probability that the second household selected will have a traditional landline telephone

[tex]p = \frac{50000}{124999} = 0.4[/tex]

0.4 = 40% probability that the second household selected will have a traditional landline telephone

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