Select all statements that are true for density curves.
the curve is on or above the horizontal axis.
the total area under the curve is 1
the curve is symmetric and single peaked
the proportion of data values between two numbers and is the area under the curve between a and b.
the curve satisfies the 68.95.99.7% rule.

The curve is on or above the horizontal axis ⇒ 1st

The total area under the curve is 1 ⇒ 2nd

The proportion of data values between two numbers and is the area

under the curve between a and b ⇒ 4th

Step-by-step explanation:

* Lets explain the meaning of density curve

- Density curve  is a mathematical model for a distribution of a variable

- It is another type of graph that represents a quantitative variables

- It describes the overall pattern of a distribution

- Its area is always on or above the horizontal axis

- Its area under the curve is exactly 1

- It can come in many shapes - symmetric, right-skewed, left-skewed

- The area under the curve and above any range of values on the

  horizontal axis is the proportion of all observations that fall in

  that range

- Ex: density curve describes the probability distribution of a

 continuous random variable

 The probability of any event is the area under the curve and above

 the values that make up the event.

* Now lets chose the true statements

# The curve is on or above the horizontal axis

# The total area under the curve is 1

# The proportion of data values between two numbers and is the area

  under the curve between a and b

a.

step-by-step explanation:

step 1 distribute 2 to every term in the parentheses

step 2 add 10 on both sides of the equal sign