There are 260 athletes at a meeting. They each give a Valentine's Day card to everyone else. How many cards were given?

When the value of the y-intercept(b) change by subtracting a number from "b" in the equation "y=mx+b", the graph will move of sh

ehidna [41]

Answer:

True. The graph will shift down if we subtract a number from "b"

Step-by-step explanation:

"b" represents the y-intercept, or how high up on the y axis the graph intersects.

If we don't change anything except for the y-intercept, then the graph should only move up or down.

Because we are decreasing the value of "b" the y intercept will decrease, dragging the graph of y down.

6 0

3 years ago

I need help with this I don't understand this math

Dmitriy789 [7]

The exponential regression equation is y = 172.21(0.99)ˣ and at x = 60 minutes y = 94.22 degree Fahrenheit and at x = 240 minutes y = 15.43 degree Fahrenheit.

<h3>What is correlation?</h3>

It is defined as the relation between two variables which is a quantitative type and gives an idea about the direction of these two variables.

$\rm r = \dfrac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{{[n\sum x^2- (\sum x)^2]}}\sqrt{[n\sum y^2- (\sum y)^2]}}$

We have data shown in the table:

We can find the exponential regression equation using the data shown.

$\rm y = ab^x$

After calculating from the data:

a = 172.21 and b = 0.99

$\rm y = 172.21(0.99)^x$

The correlation coefficient will be:

r = -0.99

The range will be all real numbers.

The domain will be y > 0

As we can see in the graph x ∈R and y>0

After an hour,

Plug x = 60 minutes in the exponential regression equation:

$\rm y = 172.21(0.99)^{60}$

y = 94.22 degree Fahrenheit

After 4 hours, plug x = 240

$\rm y = 172.21(0.99)^{240}$

y = 15.43 degree Fahrenheit

Similarly, we can find any data from the exponential regression equation.

Thus, the exponential regression equation is y = 172.21(0.99)ˣ and at x = 60 minutes y = 94.22 degree Fahrenheit and at x = 240 minutes y = 15.43 degree Fahrenheit.

Learn more about the correlation here:

brainly.com/question/11705632

#SPJ1

7 0

2 years ago

The distribution of the average amount of sleep per night gotten by college students is roughly bell-shaped with mean 412 minute

kirza4 [7]

Answer:

$P(X$

$P(z$

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(412,68)$