I need help in the next twooo minuteeeessss plssss



The ratio of boys to girls in your new class is 5:2. There are a total of twenty-eight kids in the
class. How many girls are in the class?'

Answer:

a) Approximately normal.

b) The mean is 75 years and the standard deviation is 0.8485 years.

c) 0.9909 = 99.09% probability that the mean age exceeds 73 years

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 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.

Sample of 50 retirees

This means that [tex]n = 50[/tex]

Mean age and standard deviation are 75 and 6 years

This means that [tex]\mu = 75, \sigma = 6[/tex]

a. Describe the shape of the sampling distribution of the sample mean in this case

By the Central Limit Theorem, approximately normal.

b. Find the mean and standard error of the sampling distribution of the sample mean.

By the Central Limit Theorem, the mean is 75 and the standard error is [tex]s = \frac{6}{\sqrt{50}} = 0.8485[/tex]

c. What is the probability that the mean age exceeds 73 years?

This is 1 subtracted by the pvalue of Z when X = 73.

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

By the Central Limit Theorem

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

[tex]Z = \frac{73 - 75}{0.8485}[/tex]

[tex]Z = -2.36[/tex]

[tex]Z = -2.36[/tex] has a pvalue of 0.0091

1 - 0.0091 = 0.9909

0.9909 = 99.09% probability that the mean age exceeds 73 years

Answer:

The student made the first mistake in step 2.

Step-by-step explanation:

The work of a student to solve a set of equations first make an error in step 2 .

The elimination method is the process of eliminating one of the variables in the system of linear equations using the addition or subtraction methods in conjunction with multiplication or division of coefficients of the variables.

According to the question

Equation A: y = 4 − 2z

Equation B: 4y = 2 − 4z

Solving equation by elimination method

Step 1:

[Equation A is multiplied by −4.]

−4(y) = −4(4 − 2z)  

Equation B: 4y = 2 − 4z  

Step2:

[Equation A in Step 1 is simplified.]

-4y = -16 + 8z

Equation B: 4y = 2 − 4z

Step 3:

Both equation A and B is added

-4y = -16 + 8z

 4y = 2 − 4z  

=> 0 = -14 + 4z  

Step 4:

4z = 14

z = 3.5  

Hence, the work of a student to solve a set of equations first make an error in step 2 .

To know more about elimination method here:

https://brainly.com/question/14619835

#SPJ2

Answer:

Mean: 10

Median: 10.5

Mode: none

Step-by-step explanation:

there is no mode, mean is 10 and median is 10.5

Answer: 6

Step-by-step explanation:u divide 31.2 and 5.2

Answer:

36 miles per gallon

Step-by-step explanation:

91961 - 91709 = 252 miles driven

252 miles / 7 gallons = 36 miles per gallon

Answer:

total of 25 to clean.

did 10

has 15 left

Answer: 15

Step-by-step explanation:

Ran Needs to clean 17 cams... he already cleaned 10, so subtract 17-10... it would be 7

he finds 8 cams to clean... so we add 8+7... and it becomes 15...

brainliest appreciate

Answer:

circle

Step-by-step explanation:

Answer:

1

Step-by-step explanation:

One member in the graph only went one time which is fewer than two times.

Answer:

42

Step-by-step explanation:

¯\_(ツ)_/¯

Answer: The last one

Just find it regularly by multiplying .55 by 900 to get the answer then choose the one that will give said answer.

Also eliminate the ones that are over 100% like the 2nd and 3rd one

Since its over 50% we know 55 isnt 1/2 of 900.

Answer:

The lowest term 75/60 as an improper fraction is 5/4.

Answer:

C. 12

Step-by-step explanation:

50-15=35

35÷2.75=12.7272

Answer:

6 days

Step-by-step explanation:

Answer:

6 days

Step-by-step explanation:

1 day=1/2

2 day=1

3 day=1 and 1/2

4 day=2

5 day=2 and 1/2

6 day=3

hope this helps :)

Answer:

27

reason:

did it recently

X=38

Hope I helped :]

Answer: 1/2 and 2/3

Step-by-step explanation:

Answer:30

Step-by-step explanation:

Answer: The scale factor is 3:1 because if you look at the T Point to T', it has a space of 3. Pardon for any mistakes. Good Luck!

Step-by-step explanation:

Answer:

70%

Step-by-step explanation:

42/60 = 7/10

Answer:

[tex]\frac{13}{204}[/tex] ≈ 0.0637

Step-by-step explanation:

Given: Two cards are drawn without replacement from a standard deck of 52 playing cards.

To find: probability of choosing a heart and then, without replacement, a spade

Solution:

Probability refers to chance of occurrence of any event.

Probability = Number of favorable outcomes ÷ Total number of outcomes

Total number of cards = 52

Number of hearts = 13

So,

probability of choosing a heart = [tex]\frac{13}{52}=\frac{1}{4}[/tex]

Number of remaining cards = [tex]52-1=51[/tex]

Number of spades = 13

Probability of choosing a spade = [tex]\frac{13}{51}[/tex]

Events consisting of choosing a heart and spade are independent.

So,

Probability of choosing a heart and then, without replacement, a spade =

Probability of choosing a heart × Probability of choosing a spade

= [tex]\frac{1}{4}(\frac{13}{51})=\frac{13}{204}[/tex] ≈ 0.0637

Answer:

14

Step-by-step explanation:

3x=42 d. b. s by 3

3x/3=42/3

x=14

Answer:

B.

Step-by-step explanation:

We are given:

[tex]\displaystyle \int \sqrt{x}\Big(9x^3-2\sqrt{x}+\frac{8}{x}\Big)\, dx[/tex]

And we want to select its equivalent form.

Note that A is not valid. No integration property allows us to separate factors unless that factor is a constant.

We can simply rewrite and then distribute. First, by rewriting:

[tex]\displaystyle =\int x^{1/2}\Big(9x^3-2x^{1/2}+8x^{-1}\Big)\, dx[/tex]

Distribute. Recall exponent properties;

[tex]\displaystyle =\int(9x^{3+1/2}-2x^{1/2+1/2}+8x^{-1+1/2})\, dx[/tex]

Simplify:

[tex]\displaystyle=\int9x^{7/2}-2x+8x^{1/2}\, dx[/tex]

This can then be separated (since its addition/subtraction) and integrated individually.

Hence, our answer is B.

Answer:

54000 cube cm

Step-by-step explanation:

Let height be the height of the box kite,

Also the length of one face = 30 cm,

Hence, the total area of the kite box that is covered by the fabric

= 4 × Area of one face

= 4 × 30 × height

= 120 h

According to the question,

120 height = 7200

height = 60 cm

Hence, the height of the box = 60 cm,

The volume inside the kite = The base area of the box × Its height

= 30² × 60

= 900 × 60

= 54000 cm³

i am just doing this so I can get more answers

Step-by-step explanation:

Answer:

8

Step-by-step explanation:

you can find matches that make 1 and add them all up

Answer:

8 because of rsm

Step-by-step explanation: