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tresset_1 [31]
3 years ago
12

Iodine-131, a radioactive substance that is effective in locating brain​ tumors, has a​ half-life of only eight days. a hospital

purchased 22 grams of the substance but had to wait seven days before it could be used. how much of the substance was left after seven ​days?
Mathematics
1 answer:
Ad libitum [116K]3 years ago
7 0
5 days/8 days = 0.625 half lives 

<span>fraction left after 0.625 half lives = (1/2)^0.625 </span>

<span>= 0.6484197773 </span>

<span>Amount left = 20*0.6484197773 gms </span>

<span>= 12.97 gms to dp <<<</span>
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According to a Pew Research Center study, in May 2011, 35% of all American adults had a smart phone (one which the user can use
taurus [48]

Answer:

z=\frac{0.4 -0.35}{\sqrt{\frac{0.35(1-0.35)}{300}}}=1.82  

p_v =P(z>1.82)=0.034  

So the p value obtained was a very low value and using the significance level given \alpha=0.1 we have p_v so we can conclude that we have enough evidence to reject the null hypothesis

And the best conclusion would be:

There is enough evidence to show that more than 35% of community college students own a smart phone (Pvalue = 0.034).

And for the second case the correct system of hypothesis is:

H0: p = 0.078; Ha: p > 0.078

Step-by-step explanation:

Data given and notation

n=300 represent the random sample taken

\hat p=\frac{120}{300}=0.4 estimated proportion of college students that have a smart phone

p_o=0.35 is the value that we want to test

\alpha=0.1 represent the significance level

Confidence=90% or 0.90

z would represent the statistic (variable of interest)

p_v represent the p value (variable of interest)  

Concepts and formulas to use  

We need to conduct a hypothesis in order to test the claim that the proportion is >0.35.:  

Null hypothesis:p\leq 0.35  

Alternative hypothesis:p > 0.35  

When we conduct a proportion test we need to use the z statistic, and the is given by:  

z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}} (1)  

The One-Sample Proportion Test is used to assess whether a population proportion \hat p is significantly different from a hypothesized value p_o.

Calculate the statistic  

Since we have all the info requires we can replace in formula (1) like this:  

z=\frac{0.4 -0.35}{\sqrt{\frac{0.35(1-0.35)}{300}}}=1.82  

Statistical decision  

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.  

The significance level provided \alpha=0.1. The next step would be calculate the p value for this test.  

Since is a right tailed test the p value would be:  

p_v =P(z>1.82)=0.034  

So the p value obtained was a very low value and using the significance level given \alpha=0.1 we have p_v so we can conclude that we have enough evidence to reject the null hypothesis

And the best conclusion would be:

There is enough evidence to show that more than 35% of community college students own a smart phone (Pvalue = 0.034).

And for the second case the correct system of hypothesis is:

H0: p = 0.078; Ha: p > 0.078

4 0
2 years ago
Find the slope of the line that passes through the pair of points (6,-2) and (5,-4).
wel

Answer:

<h2>slope = -10/7</h2>

<u>Step-by-step explanation:</u>

co-ordinates = (6,-2) (5,-4)

slope = (y² - y¹) / (x² - x¹)

slope = (-4 - 6) / (5 - (-2))

slope = (-10) / (5+2)

slope = (-10) / 7

slope = -10 / 7

6 0
2 years ago
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Answer:

i would love to help

Step-by-step explanation:

but i dont get what this is =-=

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2 years ago
Triangle GHI is similar to triangle JKL. Find the measure of side JK. Round your
ki77a [65]

Answer:

JK = 18.8

Step-by-step explanation:

7/33 = 4/JK

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Lines e and f are parallel. The mAngle9 = 80° and mAngle5 = 55°. Parallel lines e and f are cut by transversal c and d. All angl
loris [4]

Answer:

The angle measures that are correct are m<2 = 125degrees, m<8 = 55 degrees and m<14 = 100 degrees

Given the following angles from the diagram;

m<5 = 55 degrees

m<9 = 80degrees

From the diagram

m<5 = m<1 = 55 degrees (corresponding angle)

m<1 + m<2 = 180 (sum of angle on a straight line)

Hence;

55 + m<2 = 180

m<2 = 180 - 55

m<2 = 125degrees

Also;

m<5 = m<8 = 55 degrees (vertically opposite angle)

m<9 = m<13 = 80degrees

m<13 + m<14 = 180

Hence;

80 + m<14 = 180

m<14 = 180 - 80

m<14 = 100 degrees

Hence the angle measures that are correct are m<2 = 125degrees, m<8 = 55 degrees and m<14 = 100 degrees

Step-by-step explanation:

7 0
1 year ago
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