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3 years ago

Write the sum using summation notation, assuming the suggested pattern continues.

1 answer:

4 0

Hello,
First , number of numbers: (131-(-4))/9 +1=15+1=16
[(last number- first number)/ (2th number- 1th number) +1

$\sum_{i=1}^{16}{(-13+i*9) =-13 \sum_{i=1}^{16}{1} + 9*\sum_{i=1}^{16}{i}


$

$=-13*16+9*\frac{16*(1+16}{2}=-208+9*136=1016


$

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A study investigated the effectiveness of meditation training in reducing trait anxiety. The study evaluated subjects trait anxi

Setler79 [48]

Answer:

The 99% confidence interval for the population mean reduction in anxiety was (1.2, 8.6).

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 = 27 - 1 = 26

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 26 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.99}{2} = 0.995$ . So we have T = 2.7787.

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 2.7787\frac{6.9}{\sqrt{27}} = 3.7$

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 4.9 - 3.7 = 1.2.

The upper end of the interval is the sample mean added to M. So it is 4.9 + 3.7 = 8.6.

The 99% confidence interval for the population mean reduction in anxiety was (1.2, 8.6).

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2 years ago

Aaron tracks the time it takes him to mow lawns by writing coordinate points relating x, the time in hours it takes to mow a law

NARA [144]

Answer:

Slope of this line is given by:

Aaron’s rate for mowing lawns is 0.5 acres per hour

Step-by-step explanation:

It is given that time is tracked by Aaron related to x coordinate.

and the area of land mowed in acres is related to y coordinate.

Two of his points are given as:

(3, 1.5) and (5,2.5)

We know that the coordinates are represented in the form of (x,y)

i.e. first coordinate represents x coordinate and

second coordinate represents y coordinate.

So, it can be observed that:

$x_1=3, y_1=1.5\\x_2=5, y_2=2.5$

Change in x coordinate = $x_2-x_1=5-3 = 2$

i.e. total time taken is 2 hours.

Change in y coordinate = $y_2-y_1=2.5-1.5 = 1$

i.e. total land mowed taken is 1 acre.

In other words, it takes 2 hours for Aaron to mow 1 acre of land.

So, "option 1) It takes Aaron about 1 hour to mow 2 acres." is incorrect.

Rate of mowing lawn is the land mowed by Aaron in 1 hour.

Land mowed in 2 hours = 1 acre

Land mowed in 1 hours = $\frac{1}{2}$ acre i.e. 0.5 acre

Also, slope of a line is given as:

$m = \dfrac{y_2-y_1}{x_2-x_1}$

Here $y_2 - y_1 = 1$

$x_2 - x_1 = 2$

As per formula:

$m = \dfrac{1}{2} = 0.5$

So, option 2) Aaron’s rate for mowing lawns is 0.5 acres per hour.

6 0

3 years ago

Read 2 more answers

In the ordered pair (2, 3), 3 is the

LuckyWell [14K]

3=y and 2=x

Pretty sure that’s right

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2 years ago

What is i^30? 0A. -i 0B. -1 0C. 1 0D. i

kozerog [31]

Answer: B

Step-by-step explanation:

-1 will be your answer. (B)

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3 years ago

The owners of the pet sitting business have set aside $48 to purchase chewy toys for dogs, 2,

Contact [7]

6 chewy toys and 6 cat collars are needed to have the same amount or price at both stores.

<h3>Equation</h3>

An equation is an expression used to show the relationship between two or more angles and variables.

Let x represent the number of dogs and y represent the number of cats collars. Hence:

At Marco's market:

2x + 6y = 48 (1)

At Sonia's superstore:

4x + 4y = 48 (2)

Graphing both equations, the solution is at (6,6)

6 chewy toys and 6 cat collars are needed to have the same amount or price at both stores.

Find out more on Equation at: brainly.com/question/13763238

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1 year ago