The reading speed of second grade students is approximately normal, with a mean of 88 words per minute (wpm) and a standard deviation of 12 wpm. a) What is the probability a randomly selected student will read more than 95 words per minute? b) What is the probability that a random sample of 12 second grade students results in a mean reading rate of more than 95 words per minute? c) What is the probability that a random sample of 24 second grade students results in a mean reading rate of more than 95 words per minute? d) What effect does increasing the sample size have on the probability? Provide an explanation for this result.

Answers

Answer 1
"The reading speed of second grade students is approximately normal, with a mean of 88 words per minute (wpm) and a standard deviation of 12 wpm. a) What is the probability a randomly selected student will read more than 95 words per minute?"
                                                                95-88               7
Calculate the z-score for 95 wpm:  z = --------------- = --------
                                                                     12               12

This fraction is approx. equal to 0.583.

Look in the body of a table of positive z scores for this 0.583.  The table will give you a decimal fraction that represents the area to the LEFT of z=0.583.
Subtract that result from 1.000 to obtain the probability that a student's typing skills will be greater than 95 wpm.  If you have a calculator with the normal cumulative density function (normalcdf) built in, find the area under the normal curve to the left of 0.583 and then subtract this result from 1.000.

My calculator result was 1.000-0.720 = 0.280.

Related Questions

Write an expression for the calculation the product of 4 and 4 added to double the number 5

Answers

4*(4+(2*5))
4*(4+10)
4*14
56 is the answer.
4 x 4 + 5 x 2 would be an appropriate expression don't forget P.E.M.D.A.S.   Hope i could help! 


Explain how you can use doubles when multiplying with 4 to find 4x8

Answers

you can figure out what four times eight is by adding eight and eight(16) and doubling it (32)

write the slope intercept form of the equation through: (-1,3) ,parallel to y=3x-1

Answers

slopes of two parallel lines are equal

from the equation y=3x-1, slope =3

using slope m=3 and point (-1,3) , we find the y intercept

y=mx+b

3=3(-1) +b

b=6

plugging m=3 and b=6 in slope intercept form to get the equation

y=3x+6

What polyhedron can be assembled from this net??

Answers

This would be a triangular prism

math question down below

Answers

1/12 = 0.083(3 is repeat)

so answer is first one on the left
.083 and the 3 is repeating

Charlie bought 2 1/2 pound bag of oranges for $3.75. What is the cost of one pound of oranges

Answers

This is how you find the answer:
Divide 3.75 /2 1/2=1.5
3.75/2.5=1.5
Hi. The cost of a one pound bag is $1.50

To figure this out, you simply divide 2.5 into $3.75

$3.75 ÷ 2.5 lbs = $1.50

You can check your answer by adding the figures:

$1.50 for 1 lb
$1.50 for 1 lb
$0.75 (1/2 of $1.50)
$3.75 Total

Hope this helps.

Take care,
Diana

71 – 9a = 215 what is a? please show your work.

Answers

71 - 9a = 215
-9a = 215 - 71

-9a/9 = 144/9


a = 16

hope this helps

A recipe calls for 15 oz of flour for every 8 oz of milk .is the relationship between ounces of four and ounces of milk proportional explain

Answers

Yes, they are proportional because if you increase or decrease either amount they will both change. They will always have the same size. For example if I want to double the flour, I will have to double the milk as well because they have the same ratio. 

Answer:

Yes, there is a proportional relation.

Step-by-step explanation:

Given,

Ounces of flour for 8 ounces of milk = 15,

So, the ounces for 1 ounces of milk = [tex]\frac{15}{8}[/tex]

Let y be the ounces of flour for x ounces of milk,

∵ The ounces for x ounces of milk = [tex]\frac{15}{8}x[/tex]

[tex]\implies y = \frac{15}{8}x-----(1)[/tex]

Which is the required relation,

Since,

[tex]0=\frac{15}{8}(0)[/tex] ( True )

I.e. line [tex]y=\frac{15}{8}x[/tex] passes through the origin,

Hence, the relationship (1) is proportional.

Eight more than 3 times a number is equal to 5 less than twice the number. Find the number.

Answers

8+3x=2x-5
13=-x
Therefore x=-13

Determine the discriminant of 3x2 - 5x + 4 = 0
a) 20
b) 23
c) -23
d) -19

please help me :D

Answers

I think it's 23 but I don't really now cause I'm very young but hope this helps

Fatima plans to spend at least $15 and at most $20 dollars on sketch pads and pencils. If she buys 2 sketchpads, how many pemcils can she buy while staying in her price range?

Answers

The number of pencils  she can  buy while staying in her price range is from 12 to 18 pencils

let x represent  the number of pencils she can buy .

First step is to calculate the Total cost

Total cost=2($3.25) + x($0.75)

Total cost=$6.50 + $0.75x

Second step is to write the inequality

Inequality=15 ≤ 6.50 + 0.75p ≤ 20

Third step is to substract $6.50

8.50 ≤ 0.75p ≤ 13.50

Fourth step is to divide each  by 0.75

8.50/0.75=11.33

13.50/0.75=18

11.33 ≤ x ≤ 18

Therefore   The number of pencils  she can  buy while staying in her price range is  from  12 to 18 pencils

Learn more here:

https://brainly.com/question/2189473

If the circumference of one of the world's largest pizzas is 215 feet, what is its radius? Use 3.14 to approximate pi. Round to the nearest tenth.

Answers

C=2(pi)r, so  divide 215 by 6.28. r(radius)=34.2

Final answer:

The radius of the world's largest pizza with a circumference of 215 feet, using an approximation for pi of 3.14, is approximately 34.2 feet when rounded to the nearest tenth.

Explanation:

To find the radius of the world's largest pizza given its circumference of 215 feet, we use the formula for the circumference of a circle: C = 2πr, where C is the circumference, π (pi) is approximately 3.14, and r is the radius. We rearrange this formula to solve for the radius: r = C / (2π).

Substituting the given values into this equation, we get:

r = 215 feet / (2 × 3.14)

r = 215 / 6.28

r = 34.2356688 feet

Rounding to the nearest tenth gives us:

r ≈ 34.2 feet

In 2005, 8.1 x 10^10 text messages were sent in the United States

Answers

in 2005 , 8.1 x 10 to the 10th power text messages were sent in the united states.by 2007,the number of annual text messages had risen to 3.63 X 10 to the 11th power . about how many times as great was the number of text messages in 2007 than 2005?



Answer 3.63 10^11 ---------- = 0.448 10^1 =4.48 or 8.1 10^10 texting in 2007 was 4.48 times that of 2005

I will give Brainliest if you answer these 4 questions!!!!

Jeanie sells M&Ms out of her giant bag at 4 for 5 cents. The machine at the store sells you 9 for 25 cents. Which is the better deal for you? Show your work. Justify your answers in the space below

Tom sells baseball cards at 10 for 35 cents. Is that a better deal than 12 for 40 cents? Prove your thinking.

The hardware store sells sparklers for the 4th of July. They charge 19 cents a piece. The fireworks stand charges 85 cents for four. Which is the better deal? How can you tell?

Frosted flakes has 11 grams of sugar in each 1 ounce serving. Raisin Bran has 13 grams of sugar in each 1.4 ounce serving. Which one has less sugar from an ounce of cereal? How can you tell for sure? Prove your answer.

Answers

okay so
#1
4 for 5 would mean each single M&M is 1.25 (5/4)
9 for 25 would mean each single M&M is about 2.78 (25/9)
4 for 5 is the better deal

#2 
10 for 35 is 3.50 each (35/10)
12 for 40 is about 3.34 each (40/12)

#3 
85 divided by four is 21.25 meaning you'd spend about 22 cents each
the hardware store has a better deal seeing as 19 cents each is cheaper

#4
so 13 divided by 1.4 is about 9.3 so Raisin Bran has less sugar per ounce of cereal

the distance from town a to town b is 5 miles and the distance from town b to town c is 4 miles. which of the following could Not be the distance, in mile from town a to town c.
A. 1
B. 4
C. 8
D. 9
E. 10

Answers

A. 1 because a to b is 5 miles and b to c is 4 miles so it couldn't be 1 mile

The Triangle Inequality Theorem dictates that the impossible distance from town A to town C, given the distances from A to B (5 miles) and B to C (4 miles), is (E) 10 miles because it exceeds the sum of the other two sides.

The question pertains to the Triangle Inequality Theorem, which in the context given, states that the sum of the lengths of any two sides of a triangle must be greater than the length of the remaining side. Here we have two sides measured as 5 miles (from town A to town B) and 4 miles (from town B to town C).

To identify which distance could not be from town A to town C, we recognize that the third side must be less than the sum of the other two sides (5 miles + 4 miles = 9 miles), but also greater than the absolute difference between those two sides (5 miles - 4 miles = 1 mile). Therefore, the only impossible distance for the third side, based on the options provided, is 10 miles, as it exceeds the sum of the other two sides.

Options A (1 mile), B (4 miles), C (8 miles), and D (9 miles) all satisfy the Triangle Inequality Theorem and could represent the distance from town A to town C. Hence, the answer is E (10 miles).

What is the x-intercept of the line with the equation ?
1/3x+y=-15
( , 0)

Answers

To find x-intercept, set y = 0. So (1/3)x + 0 = - 15. So (1/3)x = - 15. Multiply by 3 on each side, x = -45. 

X-Int = - 45 or (- 45, 0)

P = a + b + c

Solve for c


Answers

p-a-b=c
is the solution

P=a+b+c
we can rewrite this as a+b+c=P
a+b+c-a=P-a
b+c=P-a
b+c-b=P-a-b
c=P-a-b

Pre-image ABCD was dilated to produce image A'B'C'D' .

What is the scale factor from the pre-image to the image?

Enter your answer in the box as a fraction in simplest form.


Answers

he right its 2/5  I took the yes to

Answer:

its 2/5 i took the test

Step-by-step explanation:

Mr. Winkle downloaded 34 more songs than Mrs. Winkle downloaded.
Together they downloaded 220 songs. How many songs did each download?
Please show how you got it...

Answers

220/2=110 each plus 34 for Mr Winkle.
Mr winkle had 134 and Mrs.Winkle had 76 which is the difference taken from her 110.

Mrs. Winkle downloaded 93 songs and Mr. Winkle downloaded 127 songs, which equals the total of 220 songs they downloaded together.

The total number of songs downloaded by Mr. and Mrs. Winkle is 220. If Mr. Winkle downloaded 34 more songs than Mrs. Winkle, we can set up a system of equations to solve for the number of songs each downloaded. Let x represent the number of songs Mrs. Winkle downloaded, so Mr. Winkle downloaded x + 34 songs.

The equation representing the total number of songs downloaded by both is:

x + (x + 34) = 220

Combining like terms gives us:

2x + 34 = 220

Subtracting 34 from both sides, we get:

2x = 186

Dividing both sides by 2, we find:

x = 93

So, Mrs. Winkle downloaded 93 songs and Mr. Winkle downloaded 93 + 34, which is:

Mr. Winkle downloaded 127 songs.

I forgot how to do this

Answers

Use the pythagorean theorem to find y.
a²+b²=c²
3²+4²=c²
9+16=c²
25=c²
c=5
y=5

All angles of a triangle form a sum of 180. We know there is 65 and 90 degree angles given to us. 
65+90+x=180
155+x=180
x=25

At a track meet, Samma finished the 200-meter race in 25.98 seconds. Tom finished the 100-meter race in 12.54 seconds. Which runner ran at a faster average rate?

Answers

time = distance / speed

Samma : 200/25.98 = 7.70 meters per second
Tom : 100 / 12.54 = 7.97 meters per second

so the faster runner is Tom

Answer: Tom

Step-by-step explanation:

time = distance / speed

Samma : 200/25.98 = 7.70 meters per second

Tom : 100 / 12.54 = 7.97 meters per second

so the faster runner is Tom

Please help this is my last day to get my grades up before report cards go out !!

Answers

2y=-x+8
2y+x=8
or x+2y=8

explain the difference between a linear equation in one variable and a linear equation in two variables. Give an example of each.

Answers

Linear in one variable: there is only one variable, it has a unique solution, power of variable is equal to one. For example 2x=20
Linear in two variables: there are two variables, it has infinitely many solution. For example a-b=20

Final answer:

The difference between a linear equation in one variable and in two variables lies in the number of variables and their graphical representation: a linear equation in one variable like 'x + 5 = 0' represents a point on the x-axis, while a linear equation in two variables like 'y = 2x + 3' represents a straight line on a plane.

Explanation:

Difference between a Linear Equation in One Variable and Two Variables

The main difference between a linear equation in one variable and a linear equation in two variables is the number of variables involved and how they can be graphically represented. A linear equation with one variable can be written in the form ax + b = 0, where a and b are constants, and x is the variable. This equation represents a single straight line in a two-dimensional space, where all points on the line have the same x-coordinate. For example, x + 5 = 0 is the equation of a vertical line represented by the point where x is -5.

On the other hand, a linear equation in two variables typically has the form y = mx + b, which represents a line in two-dimensional space where m is the slope of the line and b is the y-intercept. Here, x is the independent variable and y is the dependent variable. As x changes, y changes in a way that the relationship between them remains constant, making the graph a straight line. For example, y = 2x + 3 is an equation of a line with a slope of 2 and a y-intercept of 3.

When comparing the two types of equations, it's clear that linear equations in two variables can represent a broader range of relationships between two quantities, allowing for a visual representation of the relationship as a slope on a graph.

Daniel brought 2.75 pounds of Spanish fried rice to a family dinner. During the meal, Daniel and his family ate 1.25 pounds of rice. At the end, Daniel's friend took home half of the rice that was left after dinner.

Answers

There was .75 left of Spanish fried rice.

two number that have a sum of 45 twice the greater number is six more than 5 times the lesser number

Answers

the numbers will be X and Y with X being the lesser
x+y=45
2y=5x+6
now use a subtraction method to solve
x+y=45
y=45-x

2 (45-x)=5x+6
90-2x=5x+6
-7×=-84
x=12

y=45-12
y=33
so, x=12 and y=33

Jasmine is 5 years younger than twice her sisters age. If Jasmines sister is 22 years old. Then, how old is jasmine

Answers

Jasmine would be 39, because twice her sister's age is 44, and 44-5=39. :)
Jasmine is 39 years old. 

Her sister is 22 and Jasmine is 5 years younger than twice her sisters age, so 22 multiplied by 2 = 44
44 is twice her sisters age
then youd do  44-5=39 
39 is how old Jasmine is 

Corrine is organizing a bus trip to an amusement park. She has 245 people signed up to go on the trip. The coach buses can seat 55 people per bus. How many buses should Corrine hire?

Answers

Just divide 245 by 55 to find out how many buses are needed.

245/55 = 4.4545 buses

This means that Corrine needs 4.45 buses to haul everyone on the trip. However, it is ridiculous to think that it would be possible to hire only .45 of a bus, so to have our final answer, we would round up to the nearest whole number.

Corrine should hire 5 buses to shuttle everyone to the trip.

Jody is cutting wood to make picture frames. How many pieces of wood that are 10 3/4 inches long can cut from a board that is 75 1/4 inches long?
A) 7 pieces
B) 10 pieces
C) 65 pieces
D) 85 pieces

Answers

That means 75.25 / 10.75 which would be
a) 7

Rebecca is planning to visit relatives in Omaha Nebraska. She will drive 610 miles from her home in Indianapolis. On her trip back home, will she be traveling –610 miles? Use mathematical vocabulary to justify your answer.

Answers

no she wouldn't be traveling -610 miles because distance is never negative
Final answer:

Rebecca will travel another 610 miles on her way back from Omaha to Indianapolis, not -610 miles, as distance is a scalar quantity and does not adopt a negative sign. The total round trip distance is therefore 1220 miles.

Explanation:

When Rebecca returns home from her trip to Omaha, Nebraska, she will indeed travel another 610 miles. However, the use of -610 miles might be misleading in this context. In mathematics, especially when discussing distance, the concept of negative numbers often represents direction rather than decrement. Therefore, saying Rebecca will travel -610 miles could imply direction, but since she is returning to her starting point, the actual distance traveled is 610 miles, the same as her outbound trip.

Distance, as a quantity, is scalar and therefore always non-negative. When keeping track of total distance travelled, irrespective of direction, the concept of positive and negative doesn’t apply—the distance simply adds up. So, the total distance Rebecca travels (going to Omaha and then back to Indianapolis) would be 1220 miles. This demonstrates the concept of absolute value in mathematics, where the focus is on the magnitude of a number without regard to its sign.

C= 2pir solve for r
Please help me with this

Answers

C = 2* pi * r ;

is the formula for the circumference of the circle;
                      in which:
                                      C = the circumference of the circle;
                                      pi , or " π " ;  is the symbol for "pi" ; 
                                      r = the radius of the circle ; 
____________________________________________
To solve for "r" (the radius), divide each side by "2*pi" ;
         to isolate "r" (the radius) on one side of the equation;
        and to solve for "r" (the radius):
______________________________________________
C = 2*pi*r ;

C / (2*pi) = {2*pi*r} / (2*pi) ;

to get:
________________________________
C / (2*pi) = r ; 

r = C / (2*pi)  .
________________________________
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