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3 years ago

Which shows the expression below simplified? 0.00028 ÷ (7 × 10-4)

1 answer:

6 0

$0.\underbrace{00028}_{\rightarrow5places}=28\times10^{-5}\\\\0.00028:(7\times10^{-4})=\dfrac{28\times10^{-5}}{7\times10^{-4}}=\dfrac{28}{7}\times\dfrac{10^{-5}}{10^{-4}}\\\\=4\times10^{-5-(-4)}=4\times10^{-5+4}=\huge\boxed{4\times10^{-1}}\leftarrow\boxed{b.}\\\\used\ \dfrac{a^n}{a^m}=a^{n-m}$

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A student working on a summer internship in the economic research department of a large corporation studied the relation between

OverLord2011 [107]

Answer:

Step-by-step explanation:

Hello!

Y: sales of a product in a marketing district (million dollars)

X: population in a marketing district (million persons)

The objective is to test if there is a linear association between the sales of a product and the population of a marketing district.

Parameter; Estimated Value; 95 Percent Confidence limits

Intercept 7.43119 -1.18518 16.0476

Slope 0.755048 0.452886 1.05721

To test if there is or not an association between these two variables, you have to do a hypothesis test for the slope. If the slope is equal to zero, there is no linear association between the two variables, if the slope is different from zero, then there is a linear association between the variables.

So the student's hypotheses are:

H₀: β = 0

H₁: β ≠ 0

The data the student used to conclude is the 95%CI for the slope [0.452886;1.05721]

To be able to decide over an hypothesis test using a confidence interval there are several conditions to be met, one of them is that the confidence level and the significance level should be complementary, this means that if the interval was constructed using 1 - α= 0.95, then the hypothesis test should be conducted with a significance level of α= 0.05.

Considering that the value of the slope stated in the null hypothesis is not included in the given interval, i.e. zero is not included in the CI, then the decision is to reject the null hypothesis.

Then it can be concluded that there is a linear association between the sales of a product and the population in a marketing district.

Although in the context of the variables of study it makes no sense that the estimate of the intercept takes negative numbers, keep in mind that mathematically if possible and correct. This means that obtaining a negative estimate of the intercept does not represent a calculation error or problem for the regression model. In general, when this occurs, a footnote is made indicating has no biological meaning or sense in context.

After all, what you have done with the estimate is a mathematical assertion of the social variables.

I hope it helps!

3 0

3 years ago

A city has a population of 310,000 people. Suppose that each year the population grows by 9%. What will the population be after

Leno4ka [110]

Answer: 644,800

Step-by-step explanation:

This can also be solved using the terms of Arithmetic Progressions.

Let the 13 years be number of terms of the sequences (n)

Therefore ;

T₁₃ = a + ( n - 1 )d , where a = 310,000 and d = 9% of 310,000

9% of 310,000 = 9/100 x 310,000

= 27,900

so the common difference (d)

d = 27,900

Now substitute for the values in the formula above and calculate

T₁₃ = 310,000 + ( 13 - 1 ) x 27,900

= 310,000 + 12 x 27,900

= 310,000 + 334,800

= 644,800.

The population after 13 years = 644,800.

3 0

3 years ago

(sint-cost)²=1-sin(2t)

Gemiola [76]

i dont know the way you wan me to solve this but i got 1−2cos(t)sin(t)=1−2sin(t)cos(t)

4 0

3 years ago

Jenny made $221 for 13 hours of work. At the same rate, how many hours would she have to work to make $85?

Sever21 [200]

Answer: Jenny would have to work 5 hours to get $85

Step-by-step explanation:

Jenny makes $17 an hour (221/13 = 17) and 85/17 is 5

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3 years ago

Explain how you can use a basic subtraction fact to help you solve 98-30.

solniwko [45]

You do what I’d 9-3 , 8-0 , then combined it and you will get the right answer

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3 years ago