The appropriate hypothesis test for this question is the two proportions test. As the name implies, it is often used to compare existing percentages between two groups. The raw data behind the percentages must be available as the sample size becomes crucially important in determining the test statistics.
The test statistic of the two-proportion test is the Z value. When the sample becomes very large, the Z value is governed under a normal function and is commonly known as the standardized Z value
Answer:
C
Explanation:
Before making a hypothesis, background information is usually used. When you want to write a hypothesis, research is done first so that you can make the most educated guess possible.
If the crate is moving along the floor in the same direction with a constant speed, it is in dynamic equilibrium. Equilibrium means there is no net force acting on the crate.
Since there is no net force on the crate, there must be a friction force on the crate equal in magnitude and opposite in direction to the applied horizontal force. Therefore the force of friction acting on the crate is 100N.
It is b. sodium because it is in group 1
Answer:
t all= 30h
Explanation:
In this problem the speed of the plane is constant, so we can use the equations of uniform rectilinear motion, the definition of average speed is the distance traveled between the time taken.
v = d / t
Let's calculate each distance
First part of the trip
v₁ = d₁ / t₁
d₁ = v₁ t₁
d₁ = 120 t₁
Second part of the trip
v₂ = d₂ / t₂
d₂ = v₂ t₂
d₂ = 180 t₂
Total trip
v₃ = d₃ / t₃
d₃ = v₃ t₃
d₃ = 170 t₃
The total travel distance is the sum of each distance and the total time is the initial time of 5 h plus the time of the second part (t2)
d₁ + d₂ = 170 t₃
120 5 + 180 t₂ = 170 (5 + t₂)
Let's solve
600 + 180 t₂ = 850 +170 t₂
t₂ (180 -170) = 850 - 600
10 t₂ = 250
t₂ = 25 h
Therefore, the total travel time is
t all= 5 +25 = 30h
