Work out percentage change to 2 decimal places when a price of £97 is increased to £99.99

A certain article indicates that in a sample of 1,000 dog owners, 610 said that they take more pictures of their dog than of the

lbvjy [14]

Answer:

(a) The 90% confidence interval is: (0.60, 0.63) Correct interpretation is (3).

(b) The 95% confidence interval is: (0.42, 0.46) Correct interpretation is (1).

(c) First, the confidence level in part(b) is more than the confidence level in part(a) is, so the critical value of part(b) is more than the critical value of part(a), Second the margin of error in part(b) is more than than in part(a).

Step-by-step explanation:

(a)

Let X = number of dog owners who take more pictures of their dog than of their significant others or friends.

Given:

X = 610

n = 1000

Confidence level = 90%

The (1 - α)% confidence interval for population proportion is:

$CI=\hat p\pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

The sample proportion is:

$\hat p=\frac{X}{n}=\frac{610}{1000}=0.61$

The critical value of z for a 90% confidence level is:

$z_{\alpha/2}=z_{0.10/2}=z_[0.05}=1.645$

Construct a 90% confidence interval for the population proportion of dog owners who take more pictures of their dog than their significant others or friends as follows:

$CI=\hat p\pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}\\=0.61\pm 1.645\sqrt{\frac{0.61(1-0.61}{1000}}\\=0.61\pm 0.015\\=(0.595, 0.625)\\\approx(0.60, 0.63)$

Thus, the 90% confidence interval for the population proportion of dog owners who take more pictures of their dog than their significant others or friends is (0.60, 0.63).

Interpretation:

There is a 90% chance that the true proportion of dog owners who take more pictures of their dog than of their significant others or friends falls within the interval (0.60, 0.63).

Correct option is (3).

(b)

Let X = number of dog owners who are more likely to complain to their dog than to a friend.

Given:

X = 440

n = 1000

Confidence level = 95%

The (1 - α)% confidence interval for population proportion is:

$CI=\hat p\pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

The sample proportion is:

$\hat p=\frac{X}{n}=\frac{440}{1000}=0.44$

The critical value of z for a 95% confidence level is:

$z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96$

Construct a 95% confidence interval for the population proportion of dog owners who are more likely to complain to their dog than to a friend as follows:

$CI=\hat p\pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}\\=0.44\pm 1.96\sqrt{\frac{0.44(1-0.44}{1000}}\\=0.44\pm 0.016\\=(0.424, 0.456)\\\approx(0.42, 0.46)$

Thus, the 95% confidence interval for the population proportion of dog owners who are more likely to complain to their dog than to a friend is (0.42, 0.46).

Interpretation:

There is a 95% chance that the true proportion of dog owners who are more likely to complain to their dog than to a friend falls within the interval (0.42, 0.46).

Correct option is (1).

(c)

The confidence interval in part (b) is wider than the confidence interval in part (a).

The width of the interval is affected by:

The confidence level
Sample size
Standard deviation.

The confidence level in part (b) is more than that in part (a).

Because of this the critical value of z in part (b) is more than that in part (a).

Also the margin of error in part (b) is 0.016 which is more than the margin of error in part (a), 0.015.

First, the confidence level in part(b) is more than the confidence level in part(a) is, so the critical value of part(b) is more than the critical value of part(a), Second the margin of error in part(b) is more than than in part(a).

4 0

1 year ago

Lisa says that the indicated angles cannot have the same measure. Marita disagrees and says she can prove that they can have the

AlexFokin [52]

I agree with Marita, that the angles could have the same measure. This can be proven if you set the two amounts equal and solve for x.

9x - 25 + x = x + 50 + 2x - 12

To begin, we should combine like terms on both sides of the equation to start simplifying the equation.

10x - 25 = 3x + 38

Next, we should subtract 3x from both sides and add 25 to both sides to get the variable x alone on the left side of the equation.

7x = 63

Finally, we should divide both sides by 7, to get rid of the coefficient of x.

x = 9

If you plug in 9 for x in our first equation, you get that both of the angle measurements equal 65 degrees. This means that Marita is correct, because if x = 9, then the angles would have the same measure.

8 0

2 years ago

A cylinder has a base area of 28.2 m2 and a height of 3.1 m. Estimate the volume of the cylinder. A) 31 m3 B) 31 m2 Eliminate C)

Irina18 [472]

The answer can't be C or D because the unit of volume is always cubed. The formula for volume of cylinder is (pi)(r^2)(h) . The pi(r^2) part is the formula for area of a circle which is what the base of the cylinder is. Fortunately the area is already given as 28.2. Plug that into the volume formula and plug in 3.1 for the height and multiply. I get 87.42 and the answer choice B seems to be the closest option

6 0

2 years ago

Read 2 more answers

the flag of the bahamas includes an equilateral triangle. the perimeter of the triangle is p=3s, where s is the side length. use

padilas [110]

Answer:

345

Step-by-step explanation:

3!

7 0

2 years ago

What type of triangle has side lengths of 4√5, √145 and 19?