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3 years ago

The price of an item has dropped to $84 today. yesterday it was $120 . find the percentage decrease.

Mathematics

1 answer:

ddd [48]3 years ago

8 0

The price of an item has dropped to $84 today. yesterday it was $120 . find the percentage decrease.

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You are considering developing a regression equation relating a dependent variable to two independent variables. One of the vari

lys-0071 [83]

Answer:

Step-by-step explanation:

a. How many dummy variables are needed to represent the categorical variable?

We need 1 less dummy variable than outcomes for the categorical variable.

categorical variable has 2 outcomes

So, we need 2-1 = 1 dummy variable.

Answer: 1

Note: If our categorical variable had 5 outcomes, we would need 5-1 = 4 dummy variables.

b. Write the multiple regression equation relating the dependent variable to the independent variables.

Note: Depending your your professor, this can be written one of the following ways...

yhat = a + b1 x1 + bx2

yhat = b0 + b1 x1 + b2 x2

yhat = beta0hat + beta1hat x1 + betahat2 x2

where x1 is the ratio variable

and x2 is the dummy variable

c. Interpret the meaning of the coefficients in the regression equation.

b0 = the predicted value of y when x1 and x2 both equal 0.

b1 = the change in y when x1 increases by 1 unit holding x2 constant.

b2 = the predicted difference in y between the two possible outcomes of the categorical variable holding x1 constant.

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3 years ago

Lauren had no more than $23 to spend on 5 avocados. After buying them she had $3. What is the most each avocado cost?

expeople1 [14]

23÷5=4 with a remainder of $3. each avocada was 4$.

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2 years ago

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Brittany surveyed the students in three different Chemistry classes regarding the average number of hours of sleep they get each

aalyn [17]

Class B has the most consistant sleep because there is less of a difference between 6.87 and 3.65 than the other classes.

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3 years ago

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In 16% of all homes with a stay-at-home parent, the father is the stay-at-home parent (Pew Research, June 5, 2014). An independe

enot [183]

Answer:

$n = (\frac{z\sqrt{0.16*0.84}}{0.03})^2$ , in which z is related to the confidence level.

b) A sample size of 991 is needed.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

In 16% of all homes with a stay-at-home parent, the father is the stay-at-home parent

This means that $\pi = 0.16$

a. What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.03 (round up to the next whole number).

This is n for which $M = 0.03$ . So