# 11.8 Exercises  (Page 6/7)

 Page 6 / 7

## Try these multiple choice questions.

A new AIDS prevention drugs was tried on a group of 224 HIV positive patients. Forty-five (45) patients developed AIDS after four years. In a control group of 224 HIV positive patients, 68 developed AIDS after four years. We want to test whether the method of treatment reduces the proportion of patients that develop AIDS after four years or if the proportions of the treated group and the untreated group stay the same.

Let the subscript $t$ = treated patient and $\text{ut}$ = untreated patient.

The appropriate hypotheses are:

• ${H}_{o}:{p}_{t}<{p}_{\text{ut}}$ and ${H}_{a}:{p}_{t}\ge {p}_{\text{ut}}$
• ${H}_{o}:{p}_{t}\le {p}_{\text{ut}}$ and ${H}_{a}:{p}_{t}>{p}_{\text{ut}}$
• ${H}_{o}:{p}_{t}={p}_{\text{ut}}$ and ${H}_{a}:{p}_{t}\ne {p}_{\text{ut}}$
• ${H}_{o}:{p}_{t}={p}_{\text{ut}}$ and ${H}_{a}:{p}_{t}<{p}_{\text{ut}}$

D

If the $p$ -value is 0.0062 what is the conclusion (use $\alpha =0.05\text{}$ )?

• The method has no effect.
• There is sufficient evidence to conclude that the method reduces the proportion of HIV positive patients that develop AIDS after four years.
• There is sufficient evidence to conclude that the method increases the proportion of HIV positive patients that develop AIDS after four years.
• There is insufficient evidence to conclude that the method reduces the proportion of HIV positive patients that develop AIDS after four years.

B

Lesley E. Tan investigated the relationship between left-handedness and right-handedness and motor competence in preschool children. Random samples of 41 left-handers and 41 right-handers were given several tests of motor skills to determine if there is evidence of a difference between the children based on this experiment. The experiment produced the means and standard deviations shown below. Determine the appropriate test and best distribution to use for that test.

 Left-handed Right-handed Sample size 41 41 Sample mean 97.5 98.1 Sample standard deviation 17.5 19.2

• Two independent means, normal distribution
• Two independent means, student's-t distribution
• Matched or paired samples, student's-t distribution
• Two population proportions, normal distribution

B

An experiment is conducted to show that blood pressure can be consciously reduced in people trained in a “biofeedback exercise program.” Six (6) subjects were randomly selected and the blood pressure measurements were recorded before and after the training. The difference between blood pressures was calculated $\left(\text{after}-\text{before}\right)$ producing the following results: ${\overline{x}}_{d}=-\text{10}\text{.}2$ ${s}_{d}=8\text{.}4$ . Using the data, test the hypothesis that the blood pressure has decreased after the training,

The distribution for the test is

• ${t}_{5}$
• ${t}_{6}$
• $N\left(-\text{10}\text{.}2,8\text{.}4\right)$
• $N\left(-\text{10}\text{.}2,\frac{8\text{.}4}{\sqrt{6}}\right)$

A

If $\alpha =0\text{.}\text{05}$ , the $p$ -value and the conclusion are

• 0.0014; There is sufficient evidence to conclude that the blood pressure decreased after the training
• 0.0014; There is sufficient evidence to conclude that the blood pressure increased after the training
• 0.0155; There is sufficient evidence to conclude that the blood pressure decreased after the training
• 0.0155; There is sufficient evidence to conclude that the blood pressure increased after the training

C

can someone help me with some logarithmic and exponential equations.
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
a perfect square v²+2v+_
kkk nice
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
rolling four fair dice and getting an even number an all four dice
Kristine 2*2*2=8
Differences Between Laspeyres and Paasche Indices
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
is it 3×y ?
J, combine like terms 7x-4y
im not good at math so would this help me
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
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