I need help finding the slope

A book sold 39,300 copies in its first month of release. Suppose this represents 6.3% of the number of copies sold to date. How

konstantin123 [22]

Hi there! So 39,300 copies of a book were sold on debut month of release, and that represents 6.3% of all copies sold to date. To find the total amount of copies sold, we can write and solve a proportion. Set it up like this:

39,300/x = 6.3/100

We set it up like this because 39,300 is part of the total amount, and it represents 6.3% of the total book sales. Percents are parts of 100, which is why 6.3 is above 100. Let's cross multiply the values. 39,300 * 100 is 3,930,000. 6.3 * x is 6.3x. that makes 3,930,000 = 6.3x. Divide each side by 6.3 to isolate the x. 6.3x/6.3 cancels out. 3,930,000/6.3 is 623,809.5238 or 623,810 when rounded to the nearest whole number. There. The total amount of copies sold to date is about 623,810.

8 0

4 years ago

In a class of 30 students, 6 have a brother and 12 have a sister. There are 14 students

Elena-2011 [213]

30 students

14 have no siblings

that leaves 16 with siblings

6 have brothers and 12 have sisters which = 18 so 2 of the students have both a brother and a sister

2/30 students have a brother and a sister

1/15 chance

3 0

3 years ago

In the past, 21% of all homes with a stay-at-home parent, the father is the stay-at-home parent. An independent research firm ha

Afina-wow [57]

Answer:

A sample size of 79 is needed.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

$\pi = 0.21$

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.09?

A sample size of n is needed.

n is found when M = 0.09. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.09 = 1.96\sqrt{\frac{0.21*0.79}{n}}$

$0.09\sqrt{n} = 1.96\sqrt{0.21*0.79}$

$\sqrt{n} = \frac{1.96\sqrt{0.21*0.79}}{0.09}$

$(\sqrt{n})^{2} = (\frac{1.96\sqrt{0.21*0.79}}{0.09})^{2}$

$n = 78.68$

Rounding up to the nearest whole number.

A sample size of 79 is needed.

4 0

3 years ago

If A = 3r^2h^2, and (rh) increases by 100%, then the new A is how many times greater than the old A? PLEASE HELP ME!!! (Specify

Maslowich

Answer: the answer is 3

Step-by-step explanation:

An increase of 100% in the value of (rh) means the value doubles. When that doubled value is squared, the new area is 4 times the old area.The question asks how many times GREATER the new A is than the old A. 4 times AS LARGE AS is a 300% INCREASE, which is 3 TIMES LARGER THAN.So the grammatically correct answer is 3

3 0

2 years ago

Assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 20. Find the prob

Ipatiy [6.2K]

Answer:

Randomly selected adult has an IQ less than 136 is 0.9641

Step-by-step explanation:

It is given that, it is normal distribution with mean 100 and SD as 20.

So, let's use the formula of z-score

z= $\frac{x-mean}{SD}$

For this problem,

x= 136

Plug in this value into the formula

z-score= $\frac{136-100}{20}$

=1.8

Now, use z-score table to find the probability

Find the corresponding value for the row 1.8 and the column 0.00, we do get 0.9641

So, Randomly selected adult has an IQ less than 136 is 0.9641

3 0

3 years ago