Assume the population has a normal distribution. A sample of 25 randomly selected students Has a mean test score of 81.5 With a standard deviation of 10.2. Construct a 90% confidence interval for the mean test score.

Answers

Answer 1

Answer:

The 90% confidence interval for the mean test score is between 77.29 and 85.71.

Step-by-step explanation:

We have the standard deviation for the sample, so we use the t-distribution to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 25 - 1 = 24

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.064

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.064\frac{10.2}{\sqrt{25}} = 4.21[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 81.5 - 4.21 = 77.29

The upper end of the interval is the sample mean added to M. So it is 81.5 + 4.21 = 85.71.

The 90% confidence interval for the mean test score is between 77.29 and 85.71.


Related Questions

!!!HALPP!!! I rlly need help pls!!! !!!DUE IN 15 MINS!!!

Sandwich shop customers can choose the bread and meat they want. The table shows the sandwiches that were sold on a given day. What is the experimental probability that the next sandwich sold will be tuna on wheat bread?

Answers

23/137
explanation: looked up the question and found a pdf with all the answers

Plz help I am timed
The weight limit for hauling logs on a local highway is 80,000 pounds. A typical log truck weighs 30,000 pounds empty.
Write and solve and equation to find the maximum weight of lumber that the truck can carry and not exceed the weight
limit.
A. 30,000 + 80,000 = x; x = 110,000
B. 30,000 + x = 80,000; x = 50,000
C. 30,000x = 80,000; x = 2.67
D.80,000 - X= 30,000; x = 5,000

Answers

Answer:

Regular Operations

The gross weight of vehicles in regular operations (operating without a special permit) is governed by the State's bridge formula (Computed Gross Weight Table in Ala. Code §32-9-20[a][4][c]). State law allows a 10 percent tolerance for weight enforcement (Ala. Code §32-9-20[a][4][d]). See Exhibit 8 for a summary of Alabama weight provisions under regular operations.

Exhibit 8: Summary of Alabama Truck Weight Limits for Vehicles in Regular Operations

Single Axle 20,000 lbs.

Tandem Axle 34,000 lbs. on Interstate highways 36,000 lbs. on non-Interstate highways

Tridem Axle 42,000 lbs.

Gross Weight 80,000 lbs. on Interstate highways 84,000 lbs. (6 or more axles) on non-Interstate highways

Other 10 percent scale or enforcement tolerance on non-Interstate highways

Step-by-step explanation:

The points (8,2) and (9,10) fall on a particular line. What is its equation in point-slope form?

Use one of the specified points in your equation. Write your answer using integers, proper fractions, and improper fractions. Simplify all fractions.

Answers

Answer:

y - 10 = 8(x-9)

Step-by-step explanation:

m= (10-2)÷(9-8) =8

y-y1 = m(x-x1)

y-10 = 8(x-9)

Good afternoon guys and god bless!! does anyone know the answer to this?

Answers

Answer:

The answer to the question provided is horizontal or 0.

Step-by-step explanation:

Good afternoon and God bless you too <3

Let a = 5 cm, b = 12 cm, and c
= ? Using Pythagorean theorem

Answers

Answer:

c is 13.

Step-by-step explanation:

What we know:

Side a is 5 cm long.

Side b is 12 cm long.

What we need to know: What is c?

What do we do?:

a² + b² = c²

Substitute a and b for 5 and 12.

5² + 12² = c²

Find the squares of 5 and 12, which are 25 and 144.

25 + 144 = c²

Add 25 and 144 to get 169.

169 = c²

Find the square root of 169, to get c. That would be 13.

√169 = c

13 = c

Thus, side c is 13 cm long.

This is the last question on my homework, whoever answers gets brainliest!

Answers

Answer: 0.7, 0.2, 0.1

Step-by-step explanation:

For this question, you have to convert each of the fractions into decimals.

You can directly convert 7/10 into a decimal, this is 0.7

You cannot directly convert 1/5 into a decimal, so you have to convert it into tenths first.

To do this, multiply the numerator and denominator by 2

1 x 2 = 2

5 x 2 = 10

2/10

Now you can convert 2/10 directly into a decimal, this is 0.2

And finally you can convert 1/10 into a decimal, this is 0.1

hope this helps :)

Answer:

Hi! The correct answer is 0.7, 0.2, 0.1!

Step-by-step explanation:

I answered this so you can give the other person brainliest! Have a nice day!

The diagonal of a square is 60 in, as shown
in the diagram. What is the length of a side
to the nearest tenth of an inch?

Answers

Answer:

The length of side is 42.4 inches.

Step-by-step explanation:

Given that:

Diagonal of square = 60 inches

As all sides of a square are equal, thus

Side of square = x

The diagonal will be the hypotenuse of a right angled triangle.

Using Pythagorean theorem;

[tex]x^2+x^2=(60)^2\\2x^2=3600\\x^2=\frac{3600}{2}\\x^2=1800[/tex]

Taking square root on both sides

[tex]\sqrt{x^2}=\sqrt{1800}\\x=42.4[/tex]

Hence,

The length of side is 42.4 inches.

Students make 93.5 ounces of liquid soap for a craft fair. They put the soap in ​5.5-ounce bottles and sell each bottle for ​$4.50. How much do the students earn if they sell all the bottles of liquid​ soap? Explain.

fill in the blanks
The students earn ​$____ if they sell all the bottles of liquid soap. To find the amount the students​ earn, divide _____ by _____ to find the number of bottles sold. Multiply the number of bottles by ▼
5.5.
93.5.
$4.50.

Answers

$76.50
93.5/5.5=17
17x4.5=$76.50

HELP VERY URGENT! PLEASEEE HELP!

Answers

Answer:

Step-by-step explanation:

Thx for the points bbg

Solve for x: one over five (5x + 12) = 18 (2 points)

Answers

If you mean the equation 1/5 (5x +12) =18 then your answer would be x=15.6 or in the exact form of 78/5

Explanation : Start off with distributive property 1/5•5x and 1/5 •12, your equation should end up with 1x +2.4 =18 continue by using the 2.4 and doing the opposite, you will have 1x+2.4-2.4=18-2.4, after calculation you will have 1x=15.6 ,you can finish there or you can divide the 15.6 by one witch is still 15.6 , therefore getting your answer that is x=15.6

Vera went to the local salon to get a haircut. The cost was $24. Vera tipped the hair stylist 18%. What was the total cost of haircut including the tip? Round to the nearest cent.

Answers

Answer:  $28.32

=========================================================

Work Shown:

18% = 18/100 = 0.18

18% of 24 = 0.18*24 = 4.32

The tip is $4.32

Adding this tip amount onto the original bill leads to 4.32+24 = 28.32

-------------

As a slight shortcut, we can use the multiplier 1.18 to get

1.18*24 = 28.32

This works because

1.18*24 = (1+0.18)*24 = 1*24 + 0.18*24 = 24 + 0.18*24

Notice the portion "24 + 0.18*24" can be found buried in the 1.18*24 expression. I applied the distributive property.

The multiplier 1.18 represents an increase of 18%

We can think of it as

100% + 18% = 1+0.18 = 1.18

Find the value of x so that the function has the given value.

r(x)=−45x+7; r(x)=−5

Answers

Answer:

x = 3

Step-by-step explanation:

j(x) = 4/5(-5) + 7

= -4 + 7

= 3

How many solutions does 17.75x + 24 = 18.95x + 18 have?

Answers

Answer: Simplifying

17.75x + 24 = 18.95x + 18

Reorder the terms:

24 + 17.75x = 18.95x + 18

Reorder the terms:

24 + 17.75x = 18 + 18.95x

Solving

24 + 17.75x = 18 + 18.95x

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-18.95x' to each side of the equation.

24 + 17.75x + -18.95x = 18 + 18.95x + -18.95x

Combine like terms: 17.75x + -18.95x = -1.2x

24 + -1.2x = 18 + 18.95x + -18.95x

Combine like terms: 18.95x + -18.95x = 0.00

24 + -1.2x = 18 + 0.00

24 + -1.2x = 18

Add '-24' to each side of the equation.

24 + -24 + -1.2x = 18 + -24

Combine like terms: 24 + -24 = 0

0 + -1.2x = 18 + -24

-1.2x = 18 + -24

Combine like terms: 18 + -24 = -6

-1.2x = -6

Divide each side by '-1.2'.

x = 5

Simplifying

x = 5



Step-by-step explanation:

Describe and correct the error in writing the phrase as an expression?

Answers

Answer:

12 < x

Step-by-step explanation:

In writing 12 less than a number x, the expression, 12 - x is wrong because "less than" is not the same thing as "minus" (-). Rather, the sign, "<" should have been used as follows:

12 < x.


PLEASE ANSWER THIS AND IF YOU DO YOU GET
1. FOLLOW
2. BRAINLIEST

Answers

First: 0
Second: 0
Third: -5
Fourth: y=4x

xy+(2-x) x=3 y=2 z=4 LOLARI BINNER pls help ​

Answers

Answer:

5 or 7

Step-by-step explanation:

xy + (2-x)

3×2 + (2-3)

6 + (-1)

= 5

Buh if you meant (z-x) instead of (2-x)

then ......

3×2 + (4-3)

6+1

=7

Dr. Jensen, a pediatrician, has 3 annual
checkups and 1 sick visit scheduled next
Tuesday, which will fill a total of 167
minutes on her schedule. Next Wednesday,
she has 1 annual checkup and 1 sick visit
on the schedule, which should take 75
minutes. How much time is allotted for
each type of appointment?
minutes for an
minutes for a
The time allotted is
annual checkup and
sick visit

Answers

Answer:

The time allotted is 46 minutes for an annual checkup and 29 minutes for a sick visit

Step-by-step explanation:

System of Equations

It's required to write and solve a system of equations to model the situation of Dr. Jensen. Let's call the following variables:

x = time allotted for annual checkups

y = time allotted for sick visit

Dr. Jensen has 3 annual checkups and 1 sick visit for a total of 167 minutes on her schedule, thus:

3x + y = 167      [1]

It's also given she has 1 annual checkup and 1 sick visit on her schedule for a total of 75 minutes, thus:

x + y = 75        [2]

We'll solve the system formed by equations [1] and [2] using the elimination method.

Subtract [1] and [2]:

3x - x = 167 - 75

2x = 92

Divide by 2:

x = 46

Substitute in [2]:

46 + y = 75

Subtract 46:

y = 75 - 46 = 29

y = 29

The time allotted is 46 minutes for an annual checkup and 29 minutes for a sick visit

Freddie has a bag of jelly beans that has the following colours. 2 purple 1 red 4 yellow 3 orange. What is the probability that Freddie will select an orange jelly bean?\ 10% 20% 30% 40%


100 point

Answers

Answer:

30%

Step-by-step explanation:

3 out of the ten beans are orange

3/10=30%

Answer:

The answer is 30%.

Step-by-step explanation:

There are 2 purple, 1 red, 4 yellow, and 3 orange jelly beans. If you add all those together, you will get 10. So, 3 out of the 10 jelly beans are orange. That is 3/10 in fraction form. 3/10 equals to 30%, so that is your answer.  

18. Bill has 2/3 of a gallon of juice left in the container. He pours out 2/9 for
his brother. Which expression will yield the amount of juice left in the
container?

Answers

Answer:

4/9 of a gallon.

Step-by-step explanation:

Given that Bill has 2/3 of a gallon of juice in his container, and he pours out 2/9 to his brother, to determine the expression that will yield the amount of juice left in the container, the following calculation must be performed:

2/3 - 2/9 = X

2/3 = 6/9

6/9 - 2/9 = X

4/9 = X

So after serving his brother juice, Bill has 4/9 of a gallon of juice left.

help me please !!!!!!!!!!!

Answers

Answer:

Step-by-step explanation:

first choice

1/8 x +1/8 x =2/8=1/4 x

16- X = -2
Solve for x

Answers

Answer: x=18

Step-by-step explanation: 16-18=-2

Good luck! :)

Answer: -18

Step-by-step explanation:  16-x = -2

x = -16-2      [16 changes to -16 when transferred to RHS]

x = -18

Hope it helped u,

mark as the brainliest

^_^

X-3 < 10 when X=8
Solution
Not a solution

Answers

Answer: 5 < 10

Step-by-step explanation:

Answer in the picture below

the new photo **** help ! solve for x

Answers

Answer:

9 a 7

bye i am in a hurry

b bb

First one solved, you should be able to do the rest!

8. Find the area of a circle with center
(2, 3) that passes through (2,7)
Use 3.14 for a
F 12.58 units H 41.38 units?
6 25.12 units? J 50.24 units
Pls help

Answers

Answer:

Area of circle = 50.24 units

Option J is correct answer.

Step-by-step explanation:

We need to find the area of a circle with centre  (2, 3) that passes through (2,7)

The formula used to find area of circle is:

[tex]Area\: of\: circle=\pi \:r^2[/tex]

We need to find radius.

The radius can be found using the distance between points (2,3) and (2,7)

The The distance formula is: [tex]Distance = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]

Putting values and finding length

We have: [tex]x_1=2, y_1=3, x_2=2, y_2=7[/tex]

Putting values and finding distance

[tex]Distance = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\\Distance = \sqrt{(2-2)^2+(7-3)^2}\\Distance = \sqrt{(0)^2+(4)^2}\\Distance = \sqrt{0+16}\\Distance = \sqrt{16}\\Distance = 4[/tex]

So, we found Distance = 4

Therefore, the radius of circle is 4

Now, finding area:

[tex]Area\: of\: circle=\pi \:r^2\\Area\: of\: circle=3.14\times (4) ^2\\Area\: of\: circle=3.14\times 16\\Area\: of\: circle=50.24 \:units[/tex]

So, Area of circle = 50.24 units

Option J is correct answer.

A cookie recipe uses 3 cups of milk to make 12 cookies. If you make 84 cookies, how many cups of
milk did you use?

Answers

Answer:

21 cups of milk I think

Step-by-step explanation:

-5.2 - (-3.1) + 5.2 =

Answers

Answer:

the answer is 31/10

Step-by-step explanation:

Suppose SAT Critical Reading scores are normally distributed with a mean of 501 and a standard deviation of 110. A university plans to admit students whose scores are in the top 30%. What is the minimum score required for admission

Answers

Answer:

The minimum score required for admission is 558.75.

Step-by-step explanation:

When the distribution is normal, we use 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.

Suppose SAT Critical Reading scores are normally distributed with a mean of 501 and a standard deviation of 110.

This means that [tex]\mu = 501, \sigma = 110[/tex]

A university plans to admit students whose scores are in the top 30%. What is the minimum score required for admission

This is the 100 - 30 = 70th percentile, which is X when Z has a pvalue of 0.7. So X when Z = 0.525. So

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

[tex]0.525 = \frac{X - 501}{110}[/tex]

[tex]X - 501 = 0.525*110[/tex]

[tex]X = 558.75[/tex]

The minimum score required for admission is 558.75.

You have a new pool and want to know its volume. The pool is 5 feet deep and has a radius of 7 feet. How much water can a pool hold? Use 3.14 for pie.

Answers

Answer:

769.6902 (or 769.3) cubic feet of water

Step-by-step explanation:

πr^2

r = 7

5 x π(7)^2 = 769.6902 (or 769.3 using 3.14)

what is 5 + 9 = 2(4 − 7,5)

Answers

Answer:

5 + 9 = 2(4 - 7.5) = No

Step-by-step explanation:

Add: 5 + 9 = 14

Conversion a decimal number to a fraction: 7.5 = 75/

10

= 15/

2

a) Write down the decimal 7.5 divided by 1: 7.5 = 7.5/

1

b) Multiply both top and bottom by 10 for every number after the decimal point. (For example, if there are two numbers after the decimal point, then use 100, if there are three then use 1000, etc.)

7.5/

1

= 75/

10

Note: 75/

10

is called a decimal fraction.

c) Simplify and reduce the fraction

75/

10

= 15 * 5/

2 * 5

= 15 * 5/

2 * 5

= 15/

2

Subtract: 4 - 7.5 = 4/

1

- 15/

2

= 4 · 2/

1 · 2

- 15/

2

= 8/

2

- 15/

2

= 8 - 15/

2

= -7/

2

For adding, subtracting, and comparing fractions, it is suitable to adjust both fractions to a common (equal, identical) denominator. The common denominator you can calculate as the least common multiple of the both denominators - LCM(1, 2) = 2. In practice, it is enough to find the common denominator (not necessarily the lowest) by multiplying the denominators: 1 × 2 = 2. In the next intermediate step the fraction result cannot be further simplified by canceling.

In words - four minus fifteen halfs = minus seven halfs.

Multiple: 2 * the result of step No. 3 = 2 * (-7/

2

) = 2 · (-7)/

1 · 2

= -14/

2

= -7 · 2/

1 · 2

= -7

Multiply both numerators and denominators. Result fraction keep to lowest possible denominator GCD(-14, 2) = 2.

In words - two multiplied by minus seven halfs = minus seven.

Compare: the result of step No. 1 vs the result of step No. 4 = 14 vs (-7) = No

Thank you...

A small hole in the wing of a space shuttle requires a 20.7 cmଶ patch. What is the patch’s area in square kilometers (kmଶ )? If the patching material costs NASA $3.25 inଶ ⁄ , what is the cost of the patch?

Answers

Answer:

look it up

Step-by-step explanation:

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