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4 years ago

Alex swims at an average speed of 45 m/min. How far does he swim in 1 min 24 sec? m

Mathematics

2 answers:

denpristay [2]4 years ago

3 0

Answer:

63 m

Step-by-step explanation:

We know the rate in 45 m / min

We need to change the time to min

1 min 24 sec

We know that 1 min = 60 sec so 24 seconds is 24/60 ths of a minute

1 min 24/60 min

1 2/5 min

Changing to decimal form

1.4 minutes

Now we multiply by the rate to get the distance

d = r *t

d = 45 m/ min * 1.4 min

d= 63 m

babymother [125]4 years ago

3 0

Answer:

I would first divide 45 meters by 60 seconds to know now far Alex swims every second:

45/60 = .75m/second.

Then I would multiply .75×24 seconds:

.75 ×24 = 18 meters in 24 seconds.

Add the 45 meters he swam in one minute to the 18 meters he swam in 24 seconds.

He swam 63 meters in 1 minute 24 seconds.

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At a recent county fair, you observed that at one stand people's weight was forecasted, and were surprised by the accuracy (with

MatroZZZ [7]

Answer:

a)Slope: $\hat \beta_1 =\frac{7625.9}{1248.9}=6.106$

Intercept: $\hat \beta_o = 157.955 -6.106 (69.686)=-267.548$

b) $r=\frac{7625.9}{\sqrt{[1248.9][94228.8]}}=0.657$

And the determination coeffecient is $r^2 = 0.657^2 =0.432$

Step-by-step explanation:

Data given and definitions

The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.

The sum of squares "is the sum of the square of variation, where variation is defined as the spread between each individual value and the grand mean"

When we conduct a multiple regression we want to know about the relationship between several independent or predictor variables and a dependent or criterion variable.

n=110, $\sum x_i y_i = \sum (X-\bar X)(Y-\bar Y) =7625.9,\sum x^2_i=\sum (x-\bar x)^2 =1248.9 , sum y^2_i=\sum(y-\bar y)^2 =94228.8$

$\sum Y_i =17375 , \sum X_i = 7665.5$

Part a

The slope is given by this formula:

$\hat \beta_1 =\frac{\sum (x-\bar x) (y-\bar y)}{\sum (x-\bar x )^2}$

If we replace we got:

$\hat \beta_1 =\frac{7625.9}{1248.9}=6.106$

We can find the intercept with the following formula

$\hat \beta_o = \bar y -\hat \beta_1 \bar x$

We can find the average for x and y like this:

$\bar X=7665.5/110 =69.686, \bar y= 17375/110=157.955$

And replacing we got:

$\hat \beta_o = 157.955 -6.106 (69.686)=-267.548$

Part b

In order to calculate the correlation coefficient we can use this formula:

$r=\frac{\sum (x-\bar x)(y-\bar y) }{\sqrt{[\sum (x-\bar x)^2][\sum(y-\bar y)^2]}}$

For our case we have this:

n=110, $\sum x_i y_i = \sum (X-\bar X)(Y-\bar Y) =7625.9,\sum x^2_i=\sum (x-\bar x)^2 =1248.9 , sum y^2_i=\sum(y-\bar y)^2 =94228.8$

So we can find the correlation coefficient replacing like this:

$r=\frac{7625.9}{\sqrt{[1248.9][94228.8]}}=0.657$

And the determination coeffecient is $r^2 = 0.657^2 =0.432$

6 0

4 years ago

What is the answer too 7(1+11)-9

hodyreva [135]

75 because 7+77=84 and 84-9=75

8 0

4 years ago

Read 2 more answers

Which of the following are rational numbers {7,-5,2/3,5.79,,√13,√-4}

Ilia_Sergeevich [38]

Answer:

7, -5, 2/3, 5.79

Step-by-step explanation:

rational numbers are numbers you can put in fraction form. $\sqrt{13}$ is not a perfect square, therefore you cannot put it in fraction form. $\sqrt{-4}$ is an imaginary number. Rational numbers are in the Real Numbers category, so it is not a rational number.