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2 years ago

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A least squares regression line: a. may be used to predict a value of y if the corresponding x value is given b. implies a cause

-effect relationship between x and y c. can only be determined if a good linear relationship exists between x and y d. None of these alternatives is correct.

1 answer:

seraphim [82]2 years ago

3 0

Answer:

a) May be used to predict a value of y if the corresponding x value is given

Step-by-step explanation:

In regression analysis, the vertical distance from the regression line to the data points can be minimized using the least square regression line.

Given the example of a least square regression equation:

y = ax + b

Where

a = slope

b = Y-intercept

If the value of x is known, the value of y may be predicted.

Option A is correct.

A least squares regression line may be used to predict a value of y if the corresponding x value is given

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Nakita rode her skateboard at an average speed of 8.8 feet per second for 0.2 miles. She wants to calculate how long it took her

timama [110]

Answer: $2\ minutes$

Step-by-step explanation:

We know that:

$d=rt$

Where "d" is distance, "r" is rate and "t" is time.

Solved for the time "t":

$t=\frac{d}{r}$

The first step is to convert the distance from miles to feet.

Since $1\ mile=5,280\ feet$ , we get:

$d=(0.2\ mi)(\frac{5,280\ ft}{1\ mi})\\\\d=1,056\ ft$

Knowing that:

$r=8.8\ \frac{ft}{s}$

We can substitute values into $t=\frac{d}{r}$ in order to find the time in seconds:

$t=\frac{1,056\ ft}{8.8\ \frac{ft}{s}}\\\\t=120\ s$

Since:

$1\ minute = 60\ seconds$

The time in minutes is:

$t=(120\ s)(\frac{1\ min}{60\ s})\\\\t=2\ min$

7 0

2 years ago

Everglades National Park is 225 mi long. What scale is needed to draw a map of Everglades National Park that is 10 in. long?

shusha [124]

Answer:

A. 1 in. = 22.5 mi

Step-by-step explanation:

Since 22.5 x 10 = 225, we can conclude that this will fit the scale needed. B. is incorrect because it is simply illogical in context with a scale and the question. C. is incorrect since 10 x 0.04 is 0.4, which does not equal 10. D. is incorrect since we need the scale to add up to equal 225 mi, not 22.5.

Hope this helps!

7 0

2 years ago

A standard weight known to weigh 10 grams. Some suspect bias in weights due to manufacturing process. To assess the accuracy of

notsponge [240]

Answer:

a) The 98% confidence interval for the mean weight is between 10.00409 grams and 10.00471 grams

b) 49 measurements are needed.

Step-by-step explanation:

Question a:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.98}{2} = 0.01$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.01 = 0.99$ , so Z = 2.327.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

$M = 2.327\frac{0.0003}{\sqrt{5}} = 0.00031$

The lower end of the interval is the sample mean subtracted by M. So it is 10.0044 - 0.00031 = 10.00409 grams

The upper end of the interval is the sample mean added to M. So it is 10 + 0.00031 = 10.00471 grams

The 98% confidence interval for the mean weight is between 10.00409 grams and 10.00471 grams.

(b) How many measurements must be averaged to get a margin of error of +/- 0.0001 with 98% confidence?

We have to find n for which M = 0.0001. So

$M = z\frac{\sigma}{\sqrt{n}}$

$0.0001 = 2.327\frac{0.0003}{\sqrt{n}}$

$0.0001\sqrt{n} = 2.327*0.0003$

$\sqrt{n} = \frac{2.327*0.0003}{0.0001}$

$(\sqrt{n})^2 = (\frac{2.327*0.0003}{0.0001})^2$

$n = 48.73$

Rounding up

49 measurements are needed.

7 0

2 years ago

Which are the roots of the quadratic function f(q) = q2 – 125? Check all that apply.

adoni [48]

The answer is positive 25 and negative 25

3 0

2 years ago

Read 2 more answers

Work out the value of (6.8x10^2) x (1.3x10^-3)

nikitadnepr [17]

Answer:

0.884

Step-by-step explanation:

6.8x10^2 = 680

1.3x10^-3 = 0.0013

680 X 0.0013 = 0.884

6 0

2 years ago