Flashcard 5 (parallel,perpendicular,correlation,direct variation)

Front

What is the value of 'r' in a strong positive correlation?

Back

r is close to +1.

Front

What is the value of 'r' in a strong negative correlation?

Back

r is close to -1.

Front

What does it mean if r = 0?

Back

There is no correlation between the variables.

Front

What is the equation of a line that is parallel to y = 2x + 3?

Back

y = 2x + b (where b is any real number).

Front

What is the equation of a line that is perpendicular to y = 2x + 3?

Back

y = -0.5x + b (the slope is the negative reciprocal).

Front

If two lines intersect at a right angle, what are they called?

Back

They are called perpendicular lines.

Front

What is direct variation?

Back

A relationship where y = kx, where k is a constant.

Front

If y varies directly with x and y = 39 when x = 3, what is the constant of variation (k)?

Back

k = 13.

Front

If y = 13x, what is y when x = 2?

Back

y = 26.

Front

What does a scatter plot show?

Back

It shows the relationship between two variables.