What is the value of X ?

Answer:

[tex] P(\bar X>2.8)[/tex]

We can use the z score formula given by:

[tex] z=\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

And replacing we got:

[tex] z=\frac{2.8 -2.32}{\frac{1.24}{\sqrt{32}}}=2.190 [/tex]

And using the normal standard distribution and the complement rule we got:

[tex] P(z>2.190 )= 1-P(z<2.190) = 1-0.986=0.014[/tex]

Step-by-step explanation:

For this case w eknow the following parameters:

[tex] \mu = 2.32[/tex] represent the mean

[tex]\sigma =1.24[/tex] represent the deviation

n= 32 represent the sample sze selected

We want to find the following probability:

[tex] P(\bar X>2.8)[/tex]

We can use the z score formula given by:

[tex] z=\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

And replacing we got:

[tex] z=\frac{2.8 -2.32}{\frac{1.24}{\sqrt{32}}}=2.190 [/tex]

And using the normal standard distribution and the complement rule we got:

[tex] P(z>2.190 )= 1-P(z<2.190) = 1-0.986=0.014[/tex]

Answer:

0.55% probability that the mean childhood asthma prevalence for the sample is greater than 2.8​%. This means that a sample having an asthma prevalence of greater than 2.8% is unusual event, that is, unlikely.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

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.

If X is more than two standard deviations from the mean, it is considered an unusual outcome.

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 = 2.32, \sigma = 1.24, n = 43, s = \frac{1.24}{\sqrt{43}} = 0.189[/tex]

What is the probability that the mean childhood asthma prevalence for the sample is greater than 2.8​%?

This is 1 subtracted by the pvalue of Z when X = 2.8. So

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

By the Central Limit Theorem

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

[tex]Z = \frac{2.8 - 2.32}{0.189}[/tex]

[tex]Z = 2.54[/tex]

[tex]Z = 2.54[/tex] has a pvalue of 0.9945

1 - 0.9945 = 0.0055

0.55% probability that the mean childhood asthma prevalence for the sample is greater than 2.8​%. This means that a sample having an asthma prevalence of greater than 2.8% is unusual event, that is, unlikely.

Answer:

give $20 to each person

Step-by-step explanation:

Answer:

Step-by-step explanation:

A= New amount

P= Principal or Original amount which is £1500

I= Interest

t= time period

3.5% as a decimal is 3.5÷100=0.035

time period= 4 years

so 1500(1+0.035)^4 = B

The image of the ramp with dimensions is missing, so i have attached it.

Answer:

680 in² of wood is needed.

Step-by-step explanation:

The way to find how much wood would be needed by devon would be to find the total surface area of the ramp.

From the attached image,

Let's find the area of the 2 triangles first;

A1 = 2(½bh) = bh = 15 x 8 = 120 in²

Area of the slant rectangular portion;

A2 = 17 x 14 = 238 in²

Area of the base;

A3 = 15 × 14 = 210 in²

Area of vertical rectangle;

A4 = 8 × 14 = 112 in²

Total Surface Area = A1 + A2 + A3 + A4 = 120 + 238 + 210 + 112 = 680 in²

Answer:

The price that maximizes the profits from the sale of the product is $60.

Step-by-step explanation:

Since selling necklaces at $ 40 allows a total amount of 500 sales per week, while a price of $ 60 allows 400 sales at the same time, the following calculations must be made to determine the price that maximizes sales performance:

40 x 500 = $ 20,000

60 x 400 = $ 24,000

50 x 450 = $ 22,500

55 x 425 = $ 23,375

58 x 410 = $ 23,780

59 x 405 = $ 23,895

As can be seen from the calculations developed, the price that maximizes the profits from the sale of the product is $60.

1 × 18/100 = 12/100(g+11), is the equation. The answer is 12/100 gallons

Answer:

AC = 198

Step-by-step explanation:

Since all these points are collinear, we know that the addition of AB plus BC should give the same as AC. We can then set an equation that addresses this identity:

AB + BC = AC

5x +8 +6x - 1 = 12x - 11

Now re-arranging like terms in order to combine them:

8 - 1 + 11 = 12x - 5x - 6x

19 - 1  = 12x - 11x

18 = x

Now that we know the value of 'x", we can determine the value of AC:

AC = 12x - 11

AC = 12 (18) - 11

AC = 216 - 18

AC = 198

Answer: decimal

Step-by-step explanation:

because i did this quiz

Answer:

[tex]\frac{7}{3}[/tex]

Step-by-step explanation:

csc(Ф) is equivalent to the inverse of sin(Ф)

Since sin(Ф) = 3/7, the inverse of this would be 7/3

So, [tex]csc = \frac{1}{\frac{3}{7} }=\frac{7}{3}[/tex]

Answer:

y = 3x +1 (1)

2y = 6x +2  (2)

We can devide equation (2) by 2 and we got:

[tex] y =3x +1[/tex]   (3)

And since equations (1) and (3) are equal we can do this:

[tex] 3x +1 = 3x+1[/tex]

And that implies:

[tex] 0=0[/tex]

And for this case we will have infinite solutions for the sytem given since we have two lines equal

Step-by-step explanation:

For this case we have the following system of equations given:

y = 3x +1 (1)

2y = 6x +2  (2)

We can devide equation (2) by 2 and we got:

[tex] y =3x +1[/tex]   (3)

And since equations (1) and (3) are equal we can do this:

[tex] 3x +1 = 3x+1[/tex]

And that implies:

[tex] 0=0[/tex]

And for this case we will have infinite solutions for the sytem given since we have two lines equal

Answer:

A. Observational study

Step-by-step explanation:

In research, an observational study is a type of study in which the researcher observes a phenomenon and tries to establish some relationship between the different variables he/she is observing. In other words, the researcher only observes and doesn't give a treatment.

On the other hand, when we have a experiment, we usually have 2 different groups (one that will receive a treatment and one who won't) and the researcher compares the differences between these two groups because of the treatment. In other words, the researcher does something other than just observing.

In this example, the research is going to determine if there is a relation between hearing loss and exposure to mumps. In this example the researcher is only going to observe how people who have been exposed to mumps are regarding hearing loss (we can say this since it will be unethical for example for the researcher to create an experiment in which he/she exposes a group to mumps). Therefore, he is going to observe how the past exposure to mumps could be related with the hearing loss.

Thus, this is an observational study.

Answer:

(a) The probability that all five have used a computer while under the influence of alcohol is 0.0021.

(b) The probability that at least one has not used a computer while under the influence of alcohol is 0.9979.

(c) The probability that none of the five have used a computer while under the influence of alcohol is 0.1804.

(d) The probability that at least one has used a computer while under the influence of alcohol is 0.8196.

Step-by-step explanation:

We are given that among 25- to 30-year-olds, 29% say they have used a computer while under the influence of alcohol.

Suppose five 25- to 30-year-olds are selected at random.

The above situation can be represented through the binomial distribution;

[tex]P(X = x) = \binom{n}{r}\times p^{r} \times (1-p)^{n-r} ; x = 0,1,2,3,.........[/tex]

where, n = number of trials (samples) taken = Five 25- to 30-year-olds

            r = number of success

            p = probability of success which in our question is probability that

                  people used a computer while under the influence of alcohol,

                   i.e. p = 29%.

Let X = Number of people who used computer while under the influence of alcohol.

So, X ~ Binom(n = 5, p = 0.29)

(a) The probability that all five have used a computer while under the influence of alcohol is given by = P(X = 5)

               P(X = 5)  =  [tex]\binom{5}{5}\times 0.29^{5} \times (1-0.29)^{5-5}[/tex]

                              =  [tex]1 \times 0.29^{5} \times 0.71^{0}[/tex]

                              =  0.0021

(b) The probability that at least one has not used a computer while under the influence of alcohol is given by = P(X [tex]\geq[/tex] 1)

Here, the probability of success (p) will change because now the success for us is that people have not used a computer while under the influence of alcohol = 1 - 0.29 = 0.71

SO, now X ~ Binom(n = 5, p = 0.71)

               P(X [tex]\geq[/tex] 1)  =  1 - P(X = 0)   

                              =  [tex]1-\binom{5}{0}\times 0.71^{0} \times (1-0.71)^{5-0}[/tex]

                              =  [tex]1 -(1 \times 1 \times 0.29^{5})[/tex]

                              =  1 - 0.0021 = 0.9979.

(c) The probability that none of the five have used a computer while under the influence of alcohol is given by = P(X = 0)

               P(X = 0)  =  [tex]\binom{5}{0}\times 0.29^{0} \times (1-0.29)^{5-0}[/tex]

                              =  [tex]1 \times 1 \times 0.71^{5}[/tex]

                              =  0.1804

(d) The probability that at least one has used a computer while under the influence of alcohol is given by = P(X [tex]\geq[/tex] 1)

               P(X [tex]\geq[/tex] 1)  =  1 - P(X = 0)   

                              =  [tex]1-\binom{5}{0}\times 0.29^{0} \times (1-0.29)^{5-0}[/tex]

                              =  [tex]1 -(1 \times 1 \times 0.71^{5})[/tex]

                              =  1 - 0.1804 = 0.8196

Answer:

B.   1 over 8

Step-by-step explanation:

To determine the probability of the spinner landing on 5, we need to first know what probability is,

probability = required outcome/all possible outcome

since the spinner is divided into 8 equal sections and each section contains number from 1-8, this implies there are total of 64 numbers on the spinner.  This implies that all possible outcome = 64

In each section there is 5, since there are 8 sections on the spinner, the number of 5's on the spinner are 8.

This implies that the required outcome = 8

but

probability = required outcome/all possible outcome

probability (of the spinner landing on 5) = 8/64    =1/8

Answer:

b

Step-by-step explanation:

Answer:

difference in area = 16 ft²

if you use 8 the difference in length between Jack patio and his neighbor patio will be will be 15 - 13 = 2 ft

if you use 13 the difference i length will be 25 - 18 = 7 ft

Step-by-step explanation:

Jacks rectangular patio

width = a

length = 2a - 1

area = lw

where

l = length

w = width

area = 120 ft²

a(2a - 1)

2a² - a - 120 = 0

(a - 8) (2a + 15)

a = 8 or -15/2

Ron's rectangular patio

width = a

length = a + 5

area = lw

area = 104 ft²

a (a + 5) = 104

a² + 5a -104 = 0

(a + 8)  (a - 13)

a = -8 or 13

How many square feet longer is jack patio longer than Ron's patio is the difference in their area. Therefore,

120 - 104 = 16 ft²

The value 8 or 13 can be used for a since the width a have to be the same.

if you use 8 the difference in length between Jack patio and his neighbor patio will be will be 15 - 13 = 2 ft

if you use 13 the difference i length will be 25 - 18 = 7 ft

Answer:

False.

The null hypothesis failed to be rejected.

At a significance level of 5%, there is not enough evidence to support the claim that the entering class has a mean SAT score that is significantly lower than 1520.

Step-by-step explanation:

This is a hypothesis test for the population mean.

The claim is that the entering class has a mean SAT score that is significantly lower than 1520.

Then, the null and alternative hypothesis are:

[tex]H_0: \mu=1520\\\\H_a:\mu< 1520[/tex]

The significance level is 0.05.

The sample has a size n=20.

The sample mean is M=1501.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=53.

The estimated standard error of the mean is computed using the formula:

[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{53}{\sqrt{20}}=11.851[/tex]

Then, we can calculate the t-statistic as:

[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{1501-1520}{11.851}=\dfrac{-19}{11.851}=-1.6[/tex]

The degrees of freedom for this sample size are:

[tex]df=n-1=20-1=19[/tex]

This test is a left-tailed test, with 19 degrees of freedom and t=-1.6, so the P-value for this test is calculated as (using a t-table):

[tex]\text{P-value}=P(t<-1.6)=0.063[/tex]

As the P-value (0.063) is bigger than the significance level (0.05), the effect is not significant.

The null hypothesis failed to be rejected.

There is not enough evidence to support the claim that the entering class has a mean SAT score that is significantly lower than 1520.

Answer:

–2(5 – 4x) < 6x – 4

<=>

-10 + 8x < 6x - 4

<=>

2x < 6

<=>

x < 3

Hope this helps!

:)

Answer:

Step 1: –10 + 8x < 6x – 4

Step 2: –10 < –2x – 4

Step 3: –6 < –2x

Step 4: ________

What is the final step in solving the inequality –2(5 – 4x) < 6x – 4?

A. x < –3  

B. x > –3

C. x < 3

D. x > 3

Step-by-step explanation:

The correct answer here is C. x < 3

Answer:

160 off 20p coins

Step-by-step explanation:

20 p coins= 640 - 640*(3/8+3/8)= 640*(1- 6/8)= 640 * 2/8= 640* 1/4= 160

Answer:

x=2           x =8

Step-by-step explanation:

(x-2)(x-8)=0

Using the zero product property

x-2 = 0    x-8 = 0

x=2           x =8

Answer:x = 2 and x = 8

Step-by-step explanation:

( 2 - 2)( 8 - 8)

(0)(0)

=0

Answer:

4

Step-by-step explanation:

A=P0(1+rt).

We know that A=$3,500,P0=$2,800 and r=7.5%=0.075, so we can rearrange the formula for A to get an explicit expression for t:

A=P0(1+rt)⟹t=A−P0P0r,

and substituting the known quantities gives

r=$3,500−$2,800$2,800×0.075=3.33,

which means, since the interest is paid annually, that she must wait four years for the total investment to exceed $3,500.

Answer:

Jaleel is correct because 2 (x + 2) = 2x - 4

Step-by-step explanation:

To solve 2 (x - 2) + 2:

2 (x - 2) + 2

Distribute

2x - 4 + 2

Combine like terms

2x - 2

Lisa did not distribute correctly :)

Answer:

D

Step-by-step explanation:

Answer:

I think l

Step-by-step explanation:

first add 96 and4 then 2 I think

Answer:

21 and 10.5 respectively

Step-by-step explanation:

Remember circumference of a circle is given as;

C= 2×π×r; r is raduis

r = C / 2×π

=65.98/(2×3.142)= 10.50

D= 2× r = 2× 10.50= 21.0( D represent diameter)

Note π = 3.142 a known constant

This point is below both the red diagonal line and the blue parabola. We know that the set of solution points is below both due to the "less than" parts of each inequality sign.  

In contrast, a point like (2,2) is above the parabola which is why it is not a solution. It does not make the inequality [tex]y \le x^2-3x[/tex] true. So this is why we can rule choice A out.

Choice C is not a solution because (4,1) does not make [tex]y \le -x+3[/tex] true. This point is not below the red diagonal line. We can cross choice C off the list.

Choice D is similar to choice A, which is why we can rule it out as well.

Answer:2

Step-by-step explanation: 9+1+2=12

12\3=4

ANSWER : 2

Step-by-step explanation:

multiple 6 by 9 then 2 by 5 then subtract them

Answer:

44

Step-by-step explanation:

(6*9) - (2*5)

54 - 10

44

Answer:

The trip will take 36 minutes.

Step-by-step explanation:

This question can be solved using a rule of three.

The boat maintains a constant speed of 15 knots (nautical miles per hour). How many minutes it will take to return to its home port 9 nautical miles away?

So in 60 minutes, 15 nautical miles. How many minutes for 9 nautical miles?

60 minutes - 15 nautical miles

x minutes - 9 nautical miles

[tex]15x = 60*9[/tex]

[tex]x = \frac{60*9}{15}[/tex]

[tex]x = 36[/tex]

The trip will take 36 minutes.

Answer:

[tex]A = \dfrac{40}{P}[/tex]

Step-by-step explanation:

Pressure [tex]p(in lbs/in^2)[/tex]  varies inversely with the area [tex]A(in$ in^2)[/tex] of the sole of the shoe.

This is written as:

[tex]P \propto \frac{1}{A}\\ $Introducing the constant of variation$\\P = \dfrac{k}{A}[/tex]

When:

[tex]When: A= 40 in^2, P =4 lbs/in^2\\$Substituting into the equation\\P = \dfrac{k}{A}\\4 = \dfrac{k}{40}\\$Cross multiply\\k=4*40\\k=160\\Therefore, the equation that connect these variables is given as:\\P = \dfrac{40}{A}\\$In terms of P\\AP=40\\\\A = \dfrac{40}{P}[/tex]