You read the first 20 pages of a book in 25 minutes. You read 36 pages in 45 minutes. Is the number of pages read

Suppose you are working in an insurance company as a statistician. Your manager asked you to check police records of car acciden

pochemuha

Answer:

(a) 95% confidence interval for the percentage of all car accidents that involve teenage drivers is [0.177 , 0.243].

(b) We are 95% confident that the percentage of all car accidents that involve teenage drivers will lie between 17.7% and 24.3%.

(c) We conclude that the the percentage of teenagers has not changed since you join the company.

(d) We conclude that the the percentage of teenagers has changed since you join the company.

Step-by-step explanation:

We are given that your manager asked you to check police records of car accidents and out of 576 accidents you selected randomly, teenagers were at the wheel in 120 of them.

(a) Firstly, the pivotal quantity for 95% confidence interval for the population proportion is given by;

P.Q. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ ~ N(0,1)

where, $\hat p$ = sample proportion teenage drivers = $\frac{120}{576}$ = 0.21

n = sample of accidents = 576

p = population percentage of all car accidents

Here for constructing 95% confidence interval we have used One-sample z proportion statistics.

So, 95% confidence interval for the population population, p is ;

P(-1.96 < N(0,1) < 1.96) = 0.95 {As the critical value of z at 2.5% level

of significance are -1.96 & 1.96}

P(-1.96 < $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ < 1.96) = 0.95

P( $-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ < ${\hat p-p}$ < $1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ ) = 0.95

P( $\hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ < p < $\hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ ) = 0.95

95% confidence interval for p = [ $\hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ , $\hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ ]

= [ $0.21-1.96 \times {\sqrt{\frac{0.21(1-0.21)}{576} }}$ , $0.21+1.96 \times {\sqrt{\frac{0.21(1-0.21)}{576} }}$ ]

= [0.177 , 0.243]

Therefore, 95% confidence interval for the percentage of all car accidents that involve teenage drivers is [0.177 , 0.243].

(b) We are 95% confident that the percentage of all car accidents that involve teenage drivers will lie between 17.7% and 24.3%.

(c) We are also provided that before you were hired in the company, the percentage of teenagers who where involved in car accidents was 18%.

The manager wants to see if the percentage of teenagers has changed since you join the company.

Let p = percentage of teenagers who where involved in car accidents

So, Null Hypothesis, $H_0$ : p = 18% {means that the percentage of teenagers has not changed since you join the company}

Alternate Hypothesis, $H_A$ : p $\neq$ 18% {means that the percentage of teenagers has changed since you join the company}

The test statistics that will be used here is One-sample z proportion statistics;

T.S. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} }}$ ~ N(0,1)

where, $\hat p$ = sample proportion teenage drivers = $\frac{120}{576}$ = 0.21

n = sample of accidents = 576

So, test statistics = $\frac{0.21-0.18}{\sqrt{\frac{0.21(1-0.21)}{576} }}$

= 1.768

The value of the sample test statistics is 1.768.

Now at 0.05 significance level, the z table gives critical value of -1.96 and 1.96 for two-tailed test. Since our test statistics lies within the range of critical values of z, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which we fail to reject our null hypothesis.

Therefore, we conclude that the the percentage of teenagers has not changed since you join the company.

(d) Now at 0.1 significance level, the z table gives critical value of -1.6449 and 1.6449 for two-tailed test. Since our test statistics does not lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that the the percentage of teenagers has changed since you join the company.

4 0

2 years ago

AB is parallel to CD.

kogti [31]

Answer:

Step-by-step explanation:

∠ABC = ∠BCD { AB // CD; BC TRAVERSAL, alternate angles are equal}

∠ABC = 20

∠BCA = ∠BAC {angles opposite to equal sides are equal}

∠BCA = ∠BAC = x

x + x + 20 = 180

2x = 180 - 20

2x = 160

x = 160/2

x = 80

6 0

3 years ago

Help me please do today please help

lara31 [8.8K]

Answer:

1)

A family buys 6 tickets to a show. They also pay a $3 parking fee. They spend $27 to see the show. - 6x + 3 = 27

Explanation: As it is revealed in the situation, the family buys six tickets and the price of these tickets is unknown, so we must replace that with a variable, which gives us 6x so far. Next, it is shown that an additional three dollars were spent for a parking fee, so the next part of the equation is + 3. In total, they spend twenty-seven dollars, including the three dollars spent for the parking fee, which gives us the final part of the equation; = 27. Therefore, the equation will be 6x + 3 = 27.

Diego has 27 ounces of juice. He pours equal amounts for each of his three friends and has six ounces left for himself. - 3x + 6 = 27

Explanation: From the situation, we are told that Diego has three friends he shared the juice with and was left with six ounces for himself, meaning how much the friends took was unknown, but what was left after giving it away is clear, which was six ounces. So, the first part of the equation would be 3x + 6. It is also known that there was 27 ounces of juice at first, meaning what he shared and what he had left would equal 27, so the equation would be 3x + 6 = 27.

Jada worked for six hours preparing for the art fair. She spends three hours on a sculpture and then paints 27 picture frames. - 27x + 3 = 6

Explanation: When you first look at the story, you can see that six hours total were spent on the whole project together, meaning the final part of the equation would be = 6. The first part, however, would be concluded through how Jada spent an unknown amount of time for 27 picture frames and spent three more hours on a sculpture, which would lead to equal six. So the first part would be 27x + 3, and the actual equation for the story would be 27x + 3 = 6.

a) First story (6 tickets story) - x = price of tickets

Second story (27 ounces of juice story) - x = ounces of juice given to each friend

Third story (art project) - x = time spent on each picture frame

Important note: These are all what is unknown!

b)

6x + 3 = 27 (original equation)

Subtract three on both sides to isolate x: 6x = 24

Divide by four on both sides to isolate x: x = ($)4

3x + 6 = 27 (original equation)

Subtract by six on both sides to isolate x: 3x = 21

Divide by three on both sides to isolate x: x = 7 (oz.)

27x + 3 = 6 (original equation)

Subtract by three on both sides to isolate x: 27x = 3

Divide by twenty-seven on both sides to isolate x: x = 1/9 (hours)

c)

Diego gave each of his friends seven ounces of juice.

Inferred: We can infer that Diego had more than one friend that we was giving to. Seven ounces of juice were being given, and there are unknown amount of friends that are getting the ounces of juice.

Mommy spent $4 per person to attend the show.

Inferred: There was probably more than one person attending. The cost for one person('s ticket) was four dollars. The cost was at least $8 dollars as the mother also attended. They were trying to attend a show with an unknown amount of people.

Hope this helped somewhat! Please give brainliest, if that's okay with you! It just took a lot of effort lol :P Have a great night!

6 0

2 years ago

Who knows the answer for this question

Vadim26 [7]

Answer: 7

Work: So, the goal is to get z alone, so we are going to add 85 on both sides, cancelling on the side it's currently on. So, the new equation is going to be 25z = 175. Then, to get z even more lonely, we are going to divide 25 on both sides, and again cancelling it on the side it's currently on. So, the answer is z = 7. I hope this helps, and Happy Holidays! :)

8 0

2 years ago

Read 2 more answers

A wood stove burns 4 same-sized logs in 2 hours. How many logs does the stove burn in 8 hours?

Liono4ka [1.6K]

(4logs/2hours) = (x logs/8 hours)

(4/2) = x/8)

Cross multiplication gets you:

(4)(8) = (2)x
32 = 2x
x = 16

16 logs

8 0

2 years ago

Read 2 more answers