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

(5,-6) and (2,-6) find the distance between each pair points in units​

Answers

Answer:

The distance between the points is 3.

Step-by-step explanation:

Hope it helps ;)

Box A contains 3 red and 2 blue marbles while Box B contains 2 red and 8 blue marbles. A fair coin is tossed. If the coin turns up heads, a marble is chosen from Box A; if it turns up tails, a marble is chosen from Box B.
A. Find the probability that a red marble is chosen.
B. Referring to above information, suppose that the person who tosses the coin does not reveal whether it has turned up heads or tails (so that the box from which a marble was chosen is not revealed) but does reveal that a red marble was chosen. What is the probability that Box A was chosen (i.e., the coin turned up heads)?

Answers

Answer:

A. [tex]\frac{4}{10}[/tex]

B. [tex]\frac{3}{4}[/tex]

Step-by-step explanation:

Given - Box A contains 3 red and 2 blue marbles while Box B contains 2

            red and 8 blue marbles. A fair coin is tossed. If the coin turns up

            heads, a marble is chosen from Box A; if it turns up tails, a marble

            is chosen from Box B.

To find -  A. Find the probability that a red marble is chosen.

              B. Referring to above information, suppose that the person who

                  tosses the coin does not reveal whether it has turned up

                  heads or tails (so that the box from which a marble was

                  chosen is not revealed) but does reveal that a red marble was

                  chosen. What is the probability that Box A was chosen (i.e.,

                  the coin turned up heads)?

Proof -

As given ,

Box A : 3 red marbles and 2 blue marbles.

Box B : 2 red marbles and 8 blue marbles.

a.)

As we have to find the probability that a red marble is chosen.

A red marble is chosen in two different ways - either it can be from Box A or Box be .

If Box A is chosen , then Probability of red ball is [tex]\frac{3}{5}[/tex]

If Box B is chosen , Then Probability of Red ball is [tex]\frac{2}{10} = \frac{1}{5}[/tex]

Now,

Probability of Box A is Chosen = [tex]\frac{1}{2}[/tex]

Probability of Box B is chosen = [tex]\frac{1}{2}[/tex]

∴ we get

Probability that a Red marble is chosen =  [tex]\frac{1}{2}[/tex]×[tex]\frac{3}{5}[/tex] + [tex]\frac{1}{2}[/tex]×[tex]\frac{1}{5}[/tex] = [tex]\frac{3}{10} + \frac{1}{10} = \frac{4}{10}[/tex] = 0.4

b.)

Now,

Probability that Box A is chosen given that Red marble is chosen is

P(Box A | Red marble ) = [tex]\frac{(\frac{3}{5})(\frac{1}{2}) }{(\frac{3}{5})(\frac{1}{2}) + (\frac{1}{5})(\frac{1}{2})} = \frac{\frac{3}{10} }{\frac{3}{10} + \frac{1}{10} } = \frac{\frac{3}{10} }{\frac{4}{10}}[/tex] = [tex]\frac{3}{4}[/tex]

6) The coordinates of the origin are​

Answers

Answer:

(0,0)

Step-by-step explanation:

Required

Determine the coordinates of the origin

In geometry, the coordinates of the origin is the point where x and y are 0.

i.e.

[tex]x = 0[/tex] and [tex]y = 0[/tex]

So, the coordinate (x,y) is (0,0)

What percent is equivalent to 1/10?

Answers

Answer: 10%

Step-by-step explanation:

1/10 is equal to .10 or 10%

Answer:

10%

Step-by-step explanation:

Divide 1 by 10 and you get 0.10 :)

what does l-7l mean and whats its value NEED HELP

Answers

The lines mean absolute value which mean the number inside is the distance from 0. If the number inside is negative the absolute value is always gonna be positive for example |-7| would be 7. Hope this helps

determine the scale factor

Answers

Answer:

The scale factor is (2/3)

Step-by-step explanation:

[tex]9 \times \frac{2}{3} = 6 \\ 12 \times \frac{2}{3} = 8[/tex]

I hope that is useful for you :)

27. The length and breadth of a rectangle are in the ratio 7:5 and the perimeter is 240m, find the area of
the rectangle​

Answers

Answer:

[tex]Area = 3500[/tex]

Step-by-step explanation:

Given

[tex]Length : Breadth = 7 : 5[/tex]

[tex]Perimeter = 240m\\[/tex]

Required

Determine the area

The perimeter is:

[tex]Perimeter = 2(Length + Breadth)[/tex]

This is then represented as:

[tex]240 = 2(7x + 5x)[/tex]

[tex]240 = 2 * 12x[/tex]

[tex]240 = 24x[/tex]

[tex]10 = x[/tex]

[tex]x = 10[/tex]

So, the area is:

[tex]Area = Length * Width[/tex]

[tex]Area = 7x * 5x[/tex]

[tex]Area = 7*10 * 5*10[/tex]

[tex]Area = 3500[/tex]

HELP HELP HELP!!! NUMBER 3 PLEASE!!!

Answers

Answer:

see the attachment, answers there

Lula has two dogs, one 35 pounds, the other 25 pounds. What is the average weight of Lula's dogs?

Answers

Answer:

30

Step-by-step explanation:

25+35= 60

60/2=30

Answer: 30

Step-by-step explanation:

The term average has a number of different meanings. Most generally, it is a single number that is used to represent a collection of numbers. In the context of mathematics, "average" refers to the mean, specifically, the arithmetic mean. It is a relatively simple statistical concept that is widely used in many areas.

The equation below is one of the more commonly understood definitions of the average: [tex]Average =[/tex] [tex]\frac{Sum}{Count}[/tex]

a number added to one third of itself equals 12 . what is the number​

Answers

Answer:

9

Step-by-step explanation:

x+1/3x=12

(3x+1x)/3=12

4x/3=12

4x=12×3

4x=36

x=36/4

x=9

Answer:

1/3+x=12(cross multiply)

x+1=12*3

x+1=36(collect like terms)

x=36-1

x=35

If g(x) is 11 then what is x

Answers

If g is the inverse of a function f and
, then g'(x) is equal to

Solution :

differentitate wrt x







(f(g(x))) = 1 + (g(x))^5
g'(x) = 1 + (g(x))^5

Quadrilateral ABCD is reflected over the x-axis. What are the coordinates of
quadrilateral A'B'C'D?

Answers

Answer: A

Step-by-step explanation:

X values to the right of the y axis are positive. X values to the left of the y axis are negative.

Y values above the x axis are positive.

Y values below the x axis are negative.

Pairs of coordinates are always noted as (x,y) with the x value of a point given first and the y value of that same point given second.

Answer:

A

Step-by-step explanation:

Let A=(a,b) then the reflected over the x-axis will be A'=(a,-b)

A=(5,5) --> A'=(5,-5)

B=(5,1) --> B'=(5,-1)

C=(2,1) --> C'=(2,-1)

D=(1,5) ---> D'=(1,-5)

What is the perimeter of the triangle?

Answers

Answer: 3y + 5 cm

Step-by-step explanation: The perimeter of a triangle

is just the distance around the outside of the figure.

So just add up all the sides.

So we have y + y + y + 5 and we get 3y + 5.

g Suppose the population 10-year cumulative incidence of prostate cancer among 70-year old men is 0.06. Further, suppose 260 men without prostate cancer, aged 50 years were randomly sampled and 13 of them developed prostate cancer within 10 years. Is there evidence at the 0.05 significance level to conclude that the cumulative incidence of prostate cancer among 50-year old men differs from that of 70-year old men

Answers

Answer:

There is not enough statistical evidence to conclude that the cumulative incidence of prostrate cancer among 50-year old men differs from that of 70-year old men

Step-by-step explanation:

The population 10 year cumulative incidence of prostrate cancer among 70 year old men, p = 0.06

The number of 50 year old men in the sample, n = 260 men

The number of the sampled men that developed prostrate cancer = 13 men

The significance level, α = 0.05

Let the null hypothesis, H₀: [tex]\hat{p}[/tex] = p

The alternative hypothesis, Hₐ: [tex]\hat{p}[/tex] ≠ p

The standard score, [tex]z_{\alpha /2}[/tex] = 1.96

The test statistic, 'z', is given as follows;

[tex]z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p \cdot q}{n}}}[/tex]

[tex]\hat{p}[/tex] = 13/260 = 0.05

q = 1 - p = 1 - 0.06 = 0.94

[tex]Therefore, \ z=\dfrac{0.05-0.06}{\sqrt{\dfrac{0.06 \times 0.94}{260}}} = \dfrac{\sqrt{9165} }{141} \approx -0.68[/tex]

From the z-table, we find the p-value as follows;

P(z ≈ -0.68) = 0.24825

Therefore, given that the p-value, 0.24825 is larger than the significance level, α/2 = 0.025, we fail to reject the null hypothesis, and therefore, there is not enough statistical evidence to conclude that the cumulative incidence of prostrate cancer among 50-year old men differs from that of 70-year old men

The sum or two numbers is 59. the larger number is 15 more than the smaller number. What are the numbers

Answers

Answer: 37 and 22

Step-by-step explanation:

x + y = 59

x = 15 + y (substitute x as 15 + y into the first equation)

15 + y + y = 59

2y + 15 = 59

2y = 44

y = 22

substitute y as 22 into one of the equations

x = 15 + 22

x = 37

Horatio recorded the daily high temperatures. On 66 days, the high temperature was greater than 88°F. This was 75% of the days that Horatio recorded. How many days was the high temperature less than or equal to 88°F?

Answers

Answer:

The answer is 22

Step-by-step explanation:

The total number of days recorded by Horatio was 88,

The number of days with high temperatures less than or equal to 88°F is 22 days.

What is an expression?

An expression contains one or more terms with addition, subtraction, multiplication, and division.

We always combine the like terms in an expression when we simplify.

We also keep all the like terms on one side of the expression if we are dealing with two sides of an expression.

Example:

1 + 3x + 4y = 7 is an expression.

3 + 4 is an expression.

2 x 4 + 6 x 7 – 9 is an expression.

33 + 77 – 88 is an expression.

We have,

We know that the high temperature was greater than 88°F on 75% of the days, which means it was less than or equal to 88°F on the remaining 25% of the days.

So we can set up an equation to solve for the number of days the high temperature was less than or equal to 88°F:

So,

25% x total number of days = number of days with high temperature less than or equal to 88°F

Or in other words:

0.25 x total number of days = number of days with high temperature less than or equal to 88°F

We are given that the number of days with high temperatures greater than 88°F is 66.

Let's use x to represent the total number of days:

0.25x = number of days with high temperature less than or equal to 88°F

0.25x = x - 66

(since the number of days with high temperatures less than or equal to 88°F is the remainder)

0.25x - x = -66

-0.75x = -66

x = 88

The total number of days recorded by Horatio was 88,

The number of days with high temperatures less than or equal to 88°F.

= 0.25 x 88

= 22 days.

Thus,

The total number of days recorded by Horatio was 88,

The number of days with high temperatures less than or equal to 88°F is 22 days.

Learn more about expressions here:

https://brainly.com/question/3118662

#SPJ3

The area of the parallelogram is___ cm2

Answers

Answer:

Step-by-step explanation:

Area of parallelogram=base×perpendicular height

Area of para.= 7×14

Area of para.= 98cm²

8,626 round to the nearest thousand?

Answers

Answer:

9000

Step-by-step explanation:

What is the multiplicative inverse of y?

Answers

Answer:

The multiplicative inverse of y is [tex]\frac{1}{y}[/tex].

Step-by-step explanation:

Multiplicative inverse implies a value that you would multiply with the given value so as to give 1.

Let the multiplicative inverse of y be represented by a, so that;

a x y = 1

ay = 1

divide both sides by y to have,

a = [tex]\frac{1}{y}[/tex]

Thus, the multiplicative inverse of y is [tex]\frac{1}{y}[/tex].

This is applicable to any given value. Examples:

i. Given 2, the multiplicative inverse is [tex]\frac{1}{2}[/tex].

⇒ 2 x [tex]\frac{1}{2}[/tex] = 1

ii. What is the multiplicative inverse of 5?

The required answer is [tex]\frac{1}{5}[/tex].

Mia buys 4 ¼ pounds of plums. Her total cost after using a coupon for 55 cents off her entire purchase was $3.23. Write an equation to represent this situation.

Try to answer these

What is the total?

What will make the total - in words (be precise)

Write the words out as an equation

What don’t you know?

Write the algebraic equation.

Answers

Answer: I tried to help but i just got confused

Sorrry I didnt know the answer

I need to multiply 10,170 by 0.775​

Answers

Answer:

7881.75

Step-by-step explanation:

10,170x0.775

Answer:

7881.75

Step-by-step explanation:

Find the radius of a circle if its center is (2,3) and one point on the circle is (5,3).

Answers

Answer:

Step-by-step explanation:

radius = distance between (2,3) and (5,3) = √[(5-2)² + (3-3)²]  = 3

The required radius of the circle is

center is (2,3)
point
on the circle is (5,3).

What is radius?

Radius of the circle is the distance between the center to the circumference.

Radius = [tex]\sqrt{(X_2-X_1)^2+(Y_2-Y_1)^2}[/tex]
=[tex]\sqrt{(5-3)^2-(3-3)^2}[/tex]

Radius = [tex]\sqrt{4}[/tex]
Radius = 2

Thus, the required radius is 2 .

Learn more about radius here:
https://brainly.com/question/13449316

#SPJ2  

You NEVER distribute a coefficient of an absolute value. True or False?

Answers

Answer:

TRUE!!!!!!!!!

Step-by-step explanation:

What is the measure of angle A?
Enter your answer as a decimal in the box. Round your final answer to the nearest hundredth.

Answers

Answer: 45 degrees

Step-by-step explanation:

Answer is 45 degrees

What is the area of the triangle?
8
4

Answers

area of triangle is base x height divide by 2
8x4=32
32 divide by 2 is
16

Al abrir su alcancía Beatriz encontró que entre monedas de 5, 10 y 25 centavos completaba $ 9.50. Encontró igualmente que el número de monedas de 10 centavos era el triple de las de 25 centavos y que las de 5 centavos era el doble de las de 10 centavos. ¿Cuántas monedas de cada denominación había en la alcancía?}

Answers

Answer:

67 monedas de 5, 34 de 10 y 11 de 25.

Step-by-step explanation:

Representemos el primer enunciado de manera algebraica:

[tex]5x+10y+25z =950[/tex]  (1)

Donde:

x es el numero de monedas de 5y es el numero de monedas de 10 z es el numero de monedas de 25

Ahora, el número de monedas de 10 centavos era el triple de las de 25 centavos y que las de 5 centavos era el doble de las de 10 centavos, se puede representar como:

[tex]y=3z[/tex]  (2)              

[tex]x=2y[/tex]  (3)    

     

Combinado las eacuaciones (1), (2) y (3) tenemos:

[tex]5(2y)+10y+25(\frac{y}{3}) =950[/tex]

[tex]10y+10y+\frac{25}{3}y =950[/tex]

[tex]\frac{85}{3}y =950[/tex]  

[tex]y =34[/tex]

Por lo tanto el valor de x y z seran:

[tex]x=2(34)[/tex]          

[tex]x=68[/tex]          

[tex]z=11[/tex]    

Si ponemos cada valor en la equacion (1), tenemos:

[tex]5(68)+10(34)+25(11) =955[/tex]

Como el resultado da 955 hay un excedente de 5 pesos, asi que finalmente tendremos.

x = 67

y = 34

z = 11  

Espero te haya serrvido!


What is the sum (2 – 3i) + (-4-2i) ?

Answers

-2-5i is the correct answer

The sum of the complex numbers (2 – 3i) and (-4-2i) is -2 - 5i.

Complex numbers are numbers of the form a + bi, where a and b are real numbers and i is the imaginary unit, satisfying the equation [tex]i^2[/tex] = -1. The real part of a complex number is denoted by Re(z) = a, and the imaginary part is denoted by Im(z) = b.

Complex numbers can be added, subtracted, multiplied, and divided in a similar way to real numbers. The addition and subtraction of complex numbers is done by adding or subtracting the real and imaginary parts separately.

To find the sum of complex numbers, we add their real parts and their imaginary parts separately. Let's calculate the sum of the given complex numbers:

(2 - 3i) + (-4 - 2i)

Real part: 2 + (-4) = -2

Imaginary part: (-3i) + (-2i) = -5i

Therefore, the sum of (2 - 3i) + (-4 - 2i) is -2 - 5i.

Learn more about Complex numbers here:

https://brainly.com/question/20566728

#SPJ6

Solve the inequality for v.
5v-9> 66

Answers

Answer:

v>15

Step-by-step explanation:

add 9 to 66

5v>75

v>15

Answer: v>15

Step-by-step explanation:

The inequality can be treated as an equal sign and solved normally. Add 9 to both sides to get 5v>75, then divide to get v>15.

NOTE: If an inequality is divided by a negative number, the sign flips (> to <, etc.)

6. Cynthia walks 6 miles at a rate of 2 miles
per hour. How long will it take her to
arrive at her destination?

Answers

3 hours is the correct answer

Answer:

3

Step-by-step explanation:

6 / 2 = 3 hours


A body starts from rest and
accelerates uniform at 5 ms2.
calculate the time taken
by the body to cover a
distance of
1km

Answers

Add the numbers............
Other Questions
a caterer charges a flat delivery fee and cost per sandwich ordered.the expression 5-+4.75x represent the equation. What are the positive effects of the Coronavirus Pandemic to the mental health of people? What is the slope-intercept equation for the line below?5(4,3)(0, 1)5O A. y=2x+1B. y=-3x+1O C. y=-2x+1O D. y = 2x+1 Pls help me with this problem. Also the answer has to be in terms of pi When thermal energy is removed from matter, what happens to the molecules? Swifty Hardware reported cost of goods sold as follows. 2022 2021 Beginning inventory $ 31,000 $ 21,500 Cost of goods purchased 203,500 153,000 Cost of goods available for sale 234,500 174,500 Less: Ending inventory 35,000 31,000 Cost of goods sold $199,500 $143,500 Swifty made two errors: 1. 2021 ending inventory was overstated by $3,600. 2. 2022 ending inventory was understated by $6,550. Compute the correct cost of goods sold for each year. 2022 2021 Cost of goods sold An appliance is for sale at either (a) P15,999 cash or (b) on terms, P1,499 each month for the next 12 months. Money is 9% compounded monthly. Which is lower, the cash price or the present value of the installment terms? Explain. A math club has a total of 41 girls and boys in it. The number of girls is 5 more than 2 times the number of boys. Bert is planning to open a savings account that earns 1.6% simple interest. He wants to earn exactly $336 in interest after 3 years. How much money should he deposit helpppp please will give brainliest!! HEY can You help me with this work pls i need help don't put random. if u don't know it pls guys. Malcolm X was assassinated by members of theBlack Panthers.US Army.SNCC.Nation of Islam. albert announces to his mother, he is hungry and asks what is there to eat? she responds, go look in the refrigerator. which factor has the greatest influence on albert's food choice? 7. Bella scored 8 points in the second round. Thismade her total score 39. How many points did shescore in the first round? Motor proteins provide for molecular motion in cells by interacting with which of the following cellular structures?components of the cytoskeletonmembrane proteins of the inner nuclear envelopefree ribosomes and ribosomes attached to the ERcellulose fibers in the cell wall What were the differences between Democratic-Republicans and National Republicans? 2813.44 rounded to the nearest whole number Which of the following methods would be the easiest to use to solve 2x2 + 4x 7 = 0?A factoringB All three methods would be easy and effective.C using the quadratic formulaO isolating the x2 term and finding the square root of both sides What is the answer to the angle BD? plsss help meeeeeeeee