The time to complete an exam in a statistics class is a normal random variable with a mean of 50 minutes and a standard deviation of 10 minutes. What is the probability, given a class size of 30 students, the average time to complete the test is less than 48.5 minutes

Answers

Answer 1

Answer:

0.2061 = 20.61% probability, given a class size of 30 students, the average time to complete the test is less than 48.5 minutes

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 z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes 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.

Mean of 50 minutes and a standard deviation of 10 minutes.

This means that [tex]\mu = 50, \sigma = 10[/tex]

Class size of 30 students

This means that [tex]n = 30, s = \frac{10}{\sqrt{30}}[/tex]

What is the probability, given a class size of 30 students, the average time to complete the test is less than 48.5 minutes.

This is the p-value of Z when X = 48.5. So

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

By the Central Limit Theorem

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

[tex]Z = \frac{48.5 - 50}{\frac{10}{\sqrt{30}}}[/tex]

[tex]Z = -0.82[/tex]

[tex]Z = -0.82[/tex] has a p-value of 0.2061

0.2061 = 20.61% probability, given a class size of 30 students, the average time to complete the test is less than 48.5 minutes


Related Questions

Cho hàm số f(x, y) = ln(x
2 + y
2
).
a) Tính f

x
, f′
y
;
b) Tính f

x
(2; 1), f′
y
(2; 1).

Answers

Answer:

Sorry, I can't understand in which language you have written......

Step-by-step explanation:

So if you tell me the question in English then I can answer

Let f(x) = (x − 1)2, g(x) = e−2x, and h(x) = 1 + ln(1 − 2x). (a) Find the linearizations of f, g, and h at a = 0. What do you notice? How do you explain what happened?

Answers

Answer:

Lf(x) = Lg(x) = Lh(x) =  1 - 2x

value of the functions and their derivative are the same at x = 0

Step-by-step explanation:

Given :

f(x) = (x − 1)^2,  

g(x) = e^−2x ,  

h(x) = 1 + ln(1 − 2x).

a) Determine Linearization of  f, g and h  at a = 0

L(x) = f (a) + f'(a) (x-a)  ( linearization of f at a )

for f(x) = (x − 1)^2  

f'(x ) = 2( x - 1 )

at x = 0

f' = -2  

hence the Linearization at a = 0

Lf (x) = f(0) + f'(0) ( x - 0 )

Lf (x) = 1 -2 ( x - 0 ) = 1 - 2x

For g(x) = e^−2x

g'(x) = -2e^-2x

at x = 0

g(0) = 1

g'(0) = -2e^0 = -2

hence linearization at a = 0

Lg(x) = g ( 0 ) + g' (0) (x - 0 )

Lg(x) = 1 - 2x

For h(x) = 1 + ln(1 − 2x).

h'(x) =  -2 / ( 1 - 2x )

at x = 0

h(0) = 1

h'(0) = -2

hence linearization at a = 0

Lh(x) = h(0) + h'(0) (x-0)

        = 1 - 2x

Observation and reason

The Linearization is the same in every function i.e. Lf(x) = Lg(x) = Lh(x) this is because the value of the functions and their derivative are the same at x = 0

The probability that an individual has​ 20-20 vision is 0.18. In a class of 12 ​students, what is the probability of finding five people with​ 20-20 vision?

0.417 or 0.185 or 0.18 or 0.037

Answers

Answer:

0.417

Step-by-step explanation:

Just divide 12/5 and the answer is 0.416666666...

Round up and you get 0.417.

Hope this helped!

Melanie has D dimes and Q quarters. She has no less than $4 worth of coins altogether. Write this situation as an inequality.

Answers

Step-by-step explanation:

D(.10) + Q(.25) = 4

I think

Answer:

D(.10) + Q(.25) = 4

Step-by-step explanation:

In 2013, the Public Religion Research Institute conducted a survey of 1,033 adults, 18 years of age or older, in the continental United States. One of the questions on their survey was as follows:

Answers

Answer:

Probability[Number of people from church] = 0.26 (Approx.)

Step-by-step explanation:

Given:

Total number of adult in survey = 1,033

Missing information:

Number of people from church = 269

Find:

Probability[Number of people from church]

Computation:

Probability of an event = Number of favourable outcomes / Number of total outcomes

Probability[Number of people from church] = Number of people from church / Total number of adult in survey

Probability[Number of people from church] = 269 / 1,033

Probability[Number of people from church] = 0.2604

Probability[Number of people from church] = 0.26 (Approx.)

What is the segment

Parallel lines

Answers

Line AH and line BG are parallel

Can someone help me please?

Answers

the abswer of this question is c

The correct answer to this question is C

six options. Each of these six options leads to a menu with four options. For each of these four options, three more options are available. For each of these three options, another three options are presented. If a person calls the 800 number for assistance, how many total options are possible

Answers

Answer:

Hence the total number of possible options available to a person who calls the 800 number is 216.

Step-by-step explanation:

Given that the caller 10 800 telephone system has six options. For each of these four options, three more options are available. For each of these three options, another three options are presented.

Hence the total number of possible options available to a person who calls the 800 number = [tex]6 \times 4 \times 3 \times 3 = 216[/tex].

Which parabola opens upward?

y = 2x – 4x^2 – 5

y = 4 – 2x^2 –5x

y = 2 + 4x – 5x^2

y = –5x + 4x^2 + 2

Answers

Answer:

D) y = –5x + 4x^2 + 2

Step-by-step explanation:

You can tell by the first number being positive or negative. To check use Desmo graphing calculator and enter your equation for next time.

Omar has a gift card for $40.00 at a gift shop. Omar wants to buy a hat for himself for $13.50. For his friends, he would like to buy souvenir
bracelets, which are $3.25 each. All prices include taxes.
Which inequality can be used to solve for how many bracelets Omar can buy?
ОА.
3.25x + 13.50 S 40
OB.
3.25x + 13.50 240
Oc.
13.50x +3.25 S 40
OD.
13.50x +3.25 2 40

Answers

Answer:

A. 3.25x + 13.50 ≤ 40

The number of bracelets is x. It's a variable.

The 13.50 is a constant.

The total needs to be less than or equal to 40 because that's all the money he has.

Answer:

3.25x + 13.50 ≤ 40

Step-by-step explanation:

For this problem, you have to directly make the equation. Using the givens, it shows that he has only 40 dollars, and wants to buy only one hat for 13. 50. He wants to buy his friends braclets 3.25, but since you dont know how many friends its for, you will leave it as x.

There is only 40 dollars so you will use: ≤

The answer will be:

3.25x + 13.50 ≤ 40

Hope this helps.

In a group of 450 students, 250 like oranges 280 like apples and 40 dislike both
the fruits

Answers

Answer:

Could you please question correctly??

Step-by-step explanation:

Total Students:450

Oranges:250

Apples:280

Dislike:40

like:280-250+40

Answer

i dont see the question sorry

A papaya is accidentally dropped from a bridge, which is 30 m above the water. Ignoring air resistance, the papaya's speed just before it hits the water will be __________ m/s.

Answers

Answer:

24 .30ms is the answer I think so if the answer is correct plz mark me as brainliest.

The papaya's speed just before it hits the water will be 24.24 m/s.

What is speed?

The rate at which objects moves is called speed. It is given by

[tex]s = \frac{d}{t}[/tex]

An object held above the ground has a potential energy related to the height at which it is held,

PE = mgh

If you drop the object, its potential energy will become the kinetic energy of motion:

KE = ½ mv²

½ mv² = mgh

v  = √(2gh)

v =  √(2*9.8*30)

v =  24.24 m/s

To learn more about Speed here

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We have 9 pens, of which 5 are green ink, 3 are red ink, and 1 is black. If we put the pens in a line, how many arrangements are possible

Answers

Answer:

504 arrangements are possible

Step-by-step explanation:

Arrangements of n elements:

The number of arrangements of n elements is given by:

[tex]A_{n} = n![/tex]

Arrangements of n elements, divided into groups:

The number of arrangements of n elements, divided into groups of [tex]n_1, n_2,...,n_n[/tex] elements is given by:

[tex]A_{n}^{n_1,n_2,...,n_n} = \frac{n!}{n_1!n_2!...n_n!}[/tex]

In this case:

9 pens, into groups of 5, 3 and 1. So

[tex]A_{9}^{5,3,1} = \frac{9!}{5!3!1!} = 504[/tex]

504 arrangements are possible

Determine whether the value is a discrete random​ variable, continuous random​ variable, or not a random variable. a. The number of people with blood type A in a random sample of 26 people b. The exact time it takes to evaluate 27+72 c. The gender of college students d. The number of hits to a website in a day e. The number of bald eagles in a country f. The distance a baseball travels in the air after being hit a. Is the number of people with blood type A in a random sample of 26 people a discrete random​ variable, a continuous random​ variable, or not a random​ variable?

Answers

Answer:

a) it is a discrete random variable

b) It is a continuous random variable

c) It is not a random variable

d) It is a discrete random variable

e)  It is a discrete random variable

f) It is a continuous random variable

Step-by-step explanation:

Explanation,

Continuous Random Variable  

A continuous variable is one that can take on an uncountable set of values.

It may take any values within an interval.

It can take infinite values within an interval.

They are obtained by measuring rather than counting.

Discrete Random Variable  

These can only take a discrete value and cannot be expressed in the form of decimals.

They are obtained by counting rather than measuring.

a). it is a discrete random variable  ⇒ as a number of people is a discrete count, which takes values such as 0 or 1 or 2.

b). The exact time it takes to evaluate 27+72 ⇒ Since, Time is measured and thus it is a continuous random variable.

c). The gender of college students ⇒ Gender is categorical data. It is neither continuous nor discrete.

d).  The number of hits to a website in a day ⇒ Since the number of people cannot be expressed as decimals, thus it is a discrete random variable

e). The number of bald eagles in a country ⇒ Since the number of people cannot be expressed as decimals, thus it is a discrete random variable

f).  The distance a baseball travels in the air after being hit  ⇒ Distance is measured and thus it is a continuous random variable.

A survey was held to find the time taken by students to reach school from
their homes. Each student was asked to choose from 5, 10, 15, 20, or 25
minutes.
Number of
Minutes 5 10 15 20 25
Number of
Students
11
8
2
3
6
What is the mode for the data set?
A. 5 min b. 10 min c. 20 min d. 25 min

Answers

Hello,

in France, the mode is the value having the greater repetition

mode= 5 (repetition=11)

Will give brainliest answer, there has to be two answers to give one of you the brainliest

Answers

Answer:

C

Step-by-step explanation:

[tex] ({8}^{ { - 9})^{ \frac{ - x}{9} } } [/tex]

when putting a power to another power, then these two powers are multiplied.

so, -9 × (-x/9) = (-9 × -x) / 9 = 9x/9 = x

so, this reduces to the original

[tex] {8}^{x} [/tex]

and therefore C is the right answer.

is this right please answer ill mark!!

Answers

Answer:

yeah u r correct..

Step-by-step explanation:

hope it helps.stay safe healthy and happy......

Answer:

yes

Step-by-step explanation:

cos=adjacent over hypotenouse

Use quadratic regression to find the
equation for the parabola going
through these 3 points.
(-4, 7) (6, -33) (10, -105)
HELP PLZ

Answers

Answer:

[tex]y= -x^{2} -2x+15[/tex]

Step-by-step explanation:

 

[tex]y= -x^{2} -2x+15[/tex]

Find the area of
1.Table
Length = 123cm
Width = 82cm
Height = 76cm

2.Living room
Length = 422cm
Width = 278cm
Height = 253cm

3. Door
Length = 87cm
Width = 2.3cm
Height = 208cm​

Answers

Answer:

1. 766,536cm^3

2. 29,680,948cm^3

3. 41,620.8cm^3

Step-by-step explanation:

1. 123×82 = 10,086 10,086×76 = 766,536

2. 422×278 = 117,316 117,316×253 = 29,680,948

3. 87×2.3 = 200.1 200.1×208 = 41,620.8

Hope this helps! :)

If 128x is a perfect square number what is the least value of x

Please answer the question fast​

Answers

Answer:

in a square all sides are equal so x has to equal

128

Hope This Helps!!!

what are all the factos of 36 ​

Answers

Hi there!  

»»————- ★ ————-««

I believe your answer is:  

{1, 2, 3, 4, 6, 9, 12, 18, 36}

»»————- ★ ————-««  

Here’s why:

A factor is a whole number that is multiplied by another to have a product have another number.

⸻⸻⸻⸻

The Factors Are:

1 (1 * 36 = 36)2 (2 * 18 = 36)3 (3 * 12 = 36)4 (4 * 9 = 36)6 (6 * 6 = 36) 9 (9 * 4 = 36)12 (12 * 3 = 36)18 (18 * 2 = 36)36 (36 * 1 = 36)

⸻⸻⸻⸻

»»————- ★ ————-««  

Hope this helps you. I apologize if it’s incorrect.  

performance task number 2.
answer it correctly and I will mark brainliest.:)​

Answers

Answer:

I cant see the whole image

Step-by-step explanation:

please show it.

Plz get me the correct answer or u will be reported. 15 points for correct answer. Thx.

Answers

Answer:

D

Step-by-step explanation:

correct answer, thanks for 15 pts

Answer:

Option D is correct

Step-by-step explanation:

Hope it is helpful....

A trucking company buys 25,275 gallons of gasoline. The federal excise tax is $0.195 per gallon. Find the amount of excise tax due. (Round your answer to the nearest cent if necessary)​

Answers

Answer: 5,055

Step-by-step explanation

multiply the amount of gallons purchased by tax and round up

$4928.625 is the answer.

An Excise tax is an indirect tax, usually paid by the manufacturer or retailer of the product. then passes along in the price of the product to the consumer.

Amount of gasoline = 25,375 gallons.

The Excise tax = $0-195/gallon.

The amount of Excise tax dece = 25.875 X $0.195

= $4928.625

Se the amount of Excise tax due for 25975 gallons of gasoline is $ 4928.625

what is Excise tax?

Excise tax is generally a tax levied on the sale of a particular good or service or for a particular purpose. State excise taxes are usually levied on the sale of gasoline, air tickets, heavy trucks, road tractors, tanning beds, tires, cigarettes, and other goods and services.

Excise can be used to charge prices for externalities or to discourage the consumption of goods by others. They can also be used as royalties to generate income from people who use certain government services. Income should be used to maintain those government services.

Learn more about excise tax here:https://brainly.com/question/2871942

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38. The ______ is also not convenient to use because the process of working for it produces large numbers due to squaring. 39. The ______ is the most reliable measure of variability. 40. The lesser the variability, the ______ is the mean.​

Answers

Answer:

This Question Is From The Novel Of The Fantastic Mr.Fox

Q. Boggis , Bunce and Bean are Offering a reward for Mr.Fox , They are tired of Losing Chickens Geese and Cider , Create a Description And Drawing of Mr.Fox to allow him to be captured , use the word bank....

________________________________

Swift | Slay | Ginger | Rough | Fast

Thief. | Clever | Fur | Tail | Wife | Night

Cunning | Bushy | wiry | bush | Den | trick

________________________________

The life of light bulbs is distributed normally. The standard deviation of the lifetime is 15 hours and the mean lifetime of a bulb is 520 hours. Find the probability of a bulb lasting for at most 528 hours. Round your answer to four decimal places.

Answers

Answer:

0.7031 = 70.31% probability of a bulb lasting for at most 528 hours.

Step-by-step explanation:

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 z-score 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 p-value, we get the probability that the value of the measure is greater than X.

The standard deviation of the lifetime is 15 hours and the mean lifetime of a bulb is 520 hours.

This means that [tex]\sigma = 15, \mu = 520[/tex]

Find the probability of a bulb lasting for at most 528 hours.

This is the p-value of Z when X = 528. So

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

[tex]Z = \frac{528 - 520}{15}[/tex]

[tex]Z = 0.533[/tex]

[tex]Z = 0.533[/tex] has a p-value of 0.7031

0.7031 = 70.31% probability of a bulb lasting for at most 528 hours.

Please help me there’s a image above.

Answers

Answer:

4,-1 that is the answer so

Y=2x-8 and intercept at (-4,-1)

Answers

Answer:

y=2x+7

Step-by-step explanation:

y=2x-8

2 is the gradient.

-4 is x

-1 is y

-1=2(-4)+c

-1=-8+c

-1+8=c

c=7

therefore,

y=2x+7

Which among the following numbers could be the probability of an event? 1,1.4,-0.54,.32,.02,0

Answers

4 Answers: Choice A) 1 Choice D) 0.32 Choice E) 0.02Choice F) 0

In other words, choices B and C are the non-answers while everything else is an answer.

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

Explanation:

Let p represent the probability of an event. The value of p must be between 0 and 1, inclusive of both endpoints. Symbolically, we can write [tex]0 \le p \le 1[/tex]

In other words, p = 0 is the smallest it can get and p = 1 is the largest it can get, or it could be anything in between.

The probability p = 0 means that the event will never happen, or there's 0% of it happening. The probability p = 1 means there's 100% certainty the event will happen.

Something like p = 1.4 is not possible as this indicates it's over 100%. So that rules out choice B. Choice C is also ruled out because we can't have negative probabilities.

On a 9 question multiple-choice test, where each question has 5 answers, what would be the probability of getting at least one question wrong?

Answers

Answer:

P(at least one wrong) = 1- P(all correct) =1-.25^6=1-1/4096=4095/4096. This assumes that the answers are picked at random. This kind of question is always the complement of an extreme binomial outcome.

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