Answer:
D
Step-by-step explanation:
Parallel lines have the same gradient.
A line with a slope of zero is a horizontal line. Although two lines that have a slope of zero will result in two parallel lines, not all parallel lines are horizontal lines. Since the question is asking for which statement <u>must</u> be true, option A is incorrect.
If the slopes of two lines are negative reciprocals, they are perpendicular to each other. This is because the product of the gradients of 2 perpendicular lines is -1. Let the gradient of the first line be A and the other be B.
AB= -1
Thus, option B is incorrect too.
Undefined slopes gives vertical lines. Like option A, if two lines have an undefined slope, they will be parallel to each other. However since parallel lines are nit necessarily vertical lines, option C is also incorrect.
Answer:
0.077994
Step-by-step explanation:
Given that the owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club.
(Right tailed test)
Sample size =
Sample mean = 30.45
Mean difference =
Sample std dev s = 5
Sample std error =
Test statistic = Mean diff/std error =
Since population std deviation is not know we use t test
p value =