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2 years ago

What does the expression (x+3)(9) represent

Mathematics

1 answer:

Dominik [7]2 years ago

3 0

Answer:

evaluate 9(x+3)

expand 9x+27

Step-by-step explanation:

i think i am sorry if i am wrong

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Is a quadratic sequence (2,3,6,11) arithmetic, geometric, or neither?

Karolina [17]

Answer:

Neither

Step-by-step explanation:

It's neither. The terms do not differ (which means you add the same number to each term) by any constant amount. (Arithmetic)

The terms do not have a common number that you multiply the present term to get the next term. (Geometric)

So this one is neither.

3 0

4 years ago

A researcher has developed a new drug designed to reduce blood pressure. In an experiment, 21 subjects were assigned randomly to

Paladinen [302]

Answer:

Step-by-step explanation:

Hello!

The objective of the research is to compare the newly designed drug to reduce blood pressure with the standard drug to test if the new one is more effective.

Two randomly selected groups of subjects where determined, one took the standard drug (1- Control) and the second one took the new drug (2-New)

1. Control

X₁: Reduction of the blood pressure of a subject that took the standard drug.

n₁= 23

X[bar]= 18.52

S= 7.15

2. New

X₂: Reduction of the blood pressure of a subject that took the newly designed drug.

n₂= 21

X[bar]₂= 23.48

S₂= 8.01

The parameter of study is the difference between the two population means (no order is specified, I'll use New-Standard) μ₂ - μ₁

Assuming both variables have a normal distribution, there are two options to estimate the difference between the two means using a 95% CI.

1) The population variances are unknown and equal:

[(X[bar]₂-X[bar]₁)± $t_{n_1+n_2-2;1-\alpha /2}$ *( $Sa\sqrt{\frac{1}{n_1} +\frac{1}{n_2} }$ )]

$t_{n_1+n_2-2;1-\alpha /2}= t_{23+21-2;1-0.025}= t_{42;0.975}= 2.018$

$Sa=\sqrt{\frac{(n_1-1)*S_1^2+(n_2-1)S_2^2}{n_1+n_2-2} } = \sqrt{\frac{22*7.15^2+20*8.01^2}{42} }= 7.57$

[23.48-18.52]±2.018*( $7.57*\sqrt{\frac{1}{21} +\frac{1}{23} }$ )]

[0.349; 9.571]

2) The population variables are unknown and different:

Welche's approximation:

[(X[bar]₂-X[bar]₁)± $t_{Dfw;1-\alpha /2}$ *( $\sqrt{\frac{S_1^2}{n_1} +\frac{S_2^2}{n_2} }$ )]

$Df_{w}= \frac{(\frac{S_1^2}{n_1} +\frac{S^2_2}{n_2} )^2}{\frac{(\frac{S_1^2}{n_1} )^2}{n_1-1}+ \frac{(\frac{S_2^2}{n_2} )^2}{n_2-1} } = \frac{(\frac{7.15^2}{23} +\frac{8.01^2_2}{21} )^2}{\frac{(\frac{7.15^2}{21} )^2}{20}+ \frac{(\frac{8.01^2}{23} )^2}{22} } = 42.85= 42$

$t_{Df_w;1-\alpha /2}= t_{42; 0.975}= 2.018$

[(23.48-18.52)±2.018 $\sqrt{\frac{7.15^2}{23} +\frac{8.01^2}{21} }$ ]

[0.324; 9.596]

I hope this helps!

4 0

3 years ago

What is the product? StartFraction a minus 3 Over 15 a EndFraction times StartFraction 5 Over a minus 3 EndFraction One-third St

viva [34]

Answer:

1/3a

Step-by-step explanation:

8 0

4 years ago

Read 2 more answers

a scalene triangle has an area of 20.335 square centimeters. the height of the triangle is 8.3 centimeters. what is the length o

UNO [17]

Area of triangle = (1/2)*base*height

20.335 = (1/2)*base*8.3

2*20.335 = base*8.3

(2*20.335) / 8.3 = base Use your calculator.

4.9 = base

base = 4.9cm

5 0

3 years ago

PLEASE HELP

denis-greek [22]

The answer is d to that

8 0

3 years ago