Weekly math review 3:3

Do you expect 1/n to be larger or smaller than 1/n+1?Do you expect 1/n to be larger or smaller than 1/n+2? Explain why.

Fudgin [204]

Answer:

Step-by-step explanation:

fortnight

5 0

3 years ago

A researcher is going to estimate the average typing speed of students of a college. He selects a random sample of 20 students a

Stella [2.4K]

Answer:

The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 20 - 1 = 19

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 19 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.9}{2} = 0.95$ . So we have T = 1.7291

The margin of error is:

$M = T\frac{s}{\sqrt{n}}$

In which s is the standard deviation of the sample and n is the size of the sample. For this question, we have $s = 5, n = 20$ . So

$M = T\frac{s}{\sqrt{n}}$

$M = 1.7291\frac{5}{\sqrt{20}}$

$M = 1.933$

The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.

8 0

3 years ago

Determine and state the coordinates of the center and the length of the radius of the

zmey [24]

we can see that the center is (-3, 3) and the radius is 9 units.

<h3 /><h3>How to find the center and radius of the circle?</h3>

The general circle equation, for a circle with a center (a, b) and radius R is given by:

(x - a)^2 + (y - b)^2 = R^2

Here we have the equation:

x^2 + y^2 + 6x = 6y + 63

Let's complete squares:

x^2 + y^2 + 6x - 6y = 63

(x^2 + 6x) + (y^2 - 6y) = 63

(x^2 + 2*3x) + (y^2 - 2*3y) = 63

Now we can add and subtract 9, (two times) so we get:

(x^2 + 2*3x + 9) - 9 + (x^2 - 2*3x + 9) - 9 = 63

(x + 3)^2 + (y - 3)^2 = 63 + 9 + 9 = 81 = 9^2

(x + 3)^2 + (y - 3)^2 = 9^2

Comparing with the general circle equation, we can see that the center is (-3, 3) and the radius is 9 units.

If you want to learn more about circles:

brainly.com/question/1559324

#SPJ1

7 0

2 years ago

Hey! i’ll give brainliest please help

Ket [755]

Step-by-step explanation:

I'm guessing

second one

removing some of the sentences

7 0

2 years ago

Read 2 more answers

after 5 years of earning at an annual rate of 4 percent, an investment has earned 1200 in interest. determine the amount of the

8_murik_8 [283]

$\bf ~~~~~~ \textit{Simple Interest Earned}
\\\\
I = Prt\qquad 
\begin{cases}
I=\textit{interest earned}\to &\$1200\\
P=\textit{original amount deposited}\\
r=rate\to 4\%\to \frac{4}{100}\to &0.04\\
t=years\to &5
\end{cases}
\\\\\\
1200=P(0.04)(5)\implies \cfrac{1200}{(0.04)(5)}=P\implies 6000=P$

3 0

3 years ago