Find the sum 112.1+ 1.2

Radium-226, an isotope of radium, has a half-life of 1,601 years. Suppose your chemistry teacher has a 50-gram sample of radium-

Sholpan [36]

We know that
Half-life is modeled by the formula
An=A0*(0.5)<span>^[t/h)]
where
An----------> </span>is the amount remaining after a time t
A0----------> is the initial quantity
t------------> is the time
h------------> is the half-life of the decaying quantity

in this problem
h=1601 years
A0=50 g
An=?
t=100 years
An=A0*(0.5)^[t/h)]---------> An=50*(0.5)^[100/1601)]-----> 47.88 gr

the answer is 47.88 g

6 0

1 year ago

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Every year the state department of education gathers statistical information from all schools to award a letter grade showing th

DanielleElmas [232]

A school principal used a bar graph to send his report. He assigned the horizontal axis to the student’s name and the vertical axis to the grades. If the x-axis (the horizontal axis) is the students name and the y-axis (the vertical axis) are the grades. There has to be multiple bar-graphs per student. Otherwise the data would be incomplete.

5 0

1 year ago

There is a harvest festival each year on the planet Bozone. During that time, most of the Bozone residents sit down to rejoice a

Oliga [24]

Answer:

The price would be decreased by 18 bozats

Step-by-step explanation:

The following information is given in the question

x = number of kilograms of snig sold

P = Price per kilogram

And, the equation is

p = 300 - 18x

Now if an extra kilogram is sold so it should be x+1

Now the new price is

New price = 300 - 18(x + 1)

= 300 - 18x - 18

Therefore the price would be decreased by 18 bozats

8 0

1 year ago

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Which is the correct answer?

deff fn [24]

Answer:

The answer is H 3

Step-by-step explanation:

7 0

2 years ago

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A member of a student team playing an interactive marketing game received the fol- lowing computer output when studying the rela

nirvana33 [79]

Answer:

$p_v = 2*P(t_{n-2} > |t_{calc}|)= 0.91$

So on this case for the significance level assumed $\alpha=0.05$ we see that $p_v >\alpha$ so then we can conclude that the result is NOT significant. And we don't have enough evidence to reject the null hypothesis.

So on this case is not appropiate say that :"the more we spend on advertising this product, the fewer units we sell" since the slope for this case is not significant.

Step-by-step explanation:

Let's suppose that we have the following linear model:

$y= \beta_o +\beta_1 X$

Where Y is the dependent variable and X the independent variable. $\beta_0$ represent the intercept and $\beta_1$ the slope.

In order to estimate the coefficients $\beta_0 ,\beta_1$ we can use least squares procedure.

If we are interested in analyze if we have a significant relationship between the dependent and the independent variable we can use the following system of hypothesis:

Null Hypothesis: $\beta_1 = 0$

Alternative hypothesis: $\beta_1 \neq 0$

Or in other words we want to check is our slope is significant (X have an effect in the Y variable )

In order to conduct this test we are assuming the following conditions:

a) We have linear relationship between Y and X

b) We have the same probability distribution for the variable Y with the same deviation for each value of the independent variable

c) We assume that the Y values are independent and the distribution of Y is normal

The significance level assumed on this case is $\alpha=0.05$

The standard error for the slope is given by this formula:

$SE_{\beta_1}=\frac{\sqrt{\frac{\sum (y_i -\hat y_i)^2}{n-2}}}{\sqrt{\sum (X_i -\bar X)^2}}$

Th degrees of freedom for a linear regression is given by $df=n-2$ since we need to estimate the value for the slope and the intercept.

In order to test the hypothesis the statistic is given by:

$t=\frac{\hat \beta_1}{SE_{\beta_1}}$

The p value on this case would be given by:

$p_v = 2*P(t_{n-2} > |t_{calc}|)= 0.91$

So on this case for the significance level assumed $\alpha=0.05$ we see that $p_v >\alpha$ so then we can conclude that the result is NOT significant. And we don't have enough evidence to reject the null hypothesis.

So on this case is not appropiate say that :"the more we spend on advertising this product, the fewer units we sell" since the slope for this case is not significant.

3 0

2 years ago