All categories

3 years ago

Can someone please help me?

Mathematics

1 answer:

Eddi Din [679]3 years ago

5 0

To solve these types of problems, we need to break it down and see what each part represents.

(11) 3m
(12) j-10
(13) d+4
(14) 4p

All we must do is understand some basic keywords, such as times which represents multiplication, less which represents subtraction, and more which can represent addition or multiplication.

You might be interested in

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

3 years ago

A sweater is marked down from $25 to $18. What is the percent of change

zhenek [66]

Answer:

28 percent off is the answer :)

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

Help me asap ok thanks

Gre4nikov [31]

Answer: total profit = $418

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

Work Shown:

June

Income = (4 lawns)*($27 per lawn) = $108

Expenses = ($32 for gas)+($12 for trim line) = $44

Profit = income - expenses = 108-44 = $64

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

July

Income = (12 lawns)*($20 per lawn) = $240

Expenses = ($89 for gas)+($29 for blade sharpening) = $118

Profit = income - expenses = 240 - 89 = $151

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

August

Income = (16 lawns)*($20 per lawn) = $320

Expenses = ($101 for gas)+($16 for oil) = $117

Profit = income - expenses = 320-117 = $203

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

Total profit = (june profit)+(july profit)+(august profit)

Total profit = (64) + (151) + (203)

Total profit = $418

If the final result was negative, then we would call this a loss. However, we have a positive value, so we go with a profit.

8 0

3 years ago

For which intervals the graphs of the functions f(x) = x^3 + x^2 - 4x - 4 is positive

Nookie1986 [14]

Step-by-step explanation:

Consider a function

(

)

which is twice differentiable. The graph of such a function will be concave upwards in the intervals where the second derivative is positive and the graph will be concave downwards in the intervals where the second derivative is negative. To find these intervals we need to find the inflection points i.e. the x-values where the second derivative is 0.

5 0

3 years ago

they hold an anual pass that cost $40.00. each canoe rental costs $26.00 and each bicycle rental cost $15.00. use an algebraic e

postnew [5]

Answer:

Cost = 40.00 + 26.00c + 15.00b

Step-by-step explanation:

Let c = number of canoe rentals

and b = number of bicycle rentals. Then

Annual pass = 40.00

Canoe rentals = 26.00c

Bicycle rentals = 15.00b

Total cost = 40.00 + 26.00c + 15.00b

6 0

3 years ago