Answer:
We define the random variable X as the walking age and we are interested if American children learn to walk less than 15 months so then that would be the alternative hypothesis and the complement would be the null hypothesis.
Null hypothesis: 
Alternative hypothesis: 
And for this case the best answer would be:
H 0 : μ ≥ 15 vs. Ha : μ < 15
Step-by-step explanation:
We define the random variable X as the walking age and we are interested if American children learn to walk less than 15 months so then that would be the alternative hypothesis and the complement would be the null hypothesis.
Null hypothesis: 
Alternative hypothesis: 
And for this case the best answer would be:
H 0 : μ ≥ 15 vs. Ha : μ < 15
And the data given from the sample is:
represent the sample mean
represent the population deviation
represent the sample size
And the statistic would be given by:

No.4- This is not a triangle since one side should be less than the sum of the 2 other sides. In this case 8=3+5, hence it's equal & not smaller
N0.5- This is an isosceles triangle & there are an infinity of triangles with the mentioned degrees. (these are called similar triangle)
No6- This is a unique triangle
No.7- If the plane is parallel to the bases, then the slicing is a cercle.
But if the plane (Parallelogram) is tilt, then the slicing is an ellipse
Answer:
a
Step-by-step explanation: