Answer:
Test scores of 10.2 or lower are significantly low.
Test scores of 31.4 or higher are significantly high.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean 
and standard deviation 
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
Identify the test scores that are significantly low or significantly high.
Significantly low
Z = -2 and lower.
So the significantly low scores are thoses values that are lower or equal than X when Z = -2. So
Test scores of 10.2 or lower are significantly low.
Significantly high
Z = 2 and higher.
So the significantly high scores are thoses values that are higherr or equal than X when Z = 2. So
Test scores of 31.4 or higher are significantly high.
Answer:
The actual length of the helicopter is <u>23 feet</u>.
Step-by-step explanation:
Given:
On a scale drawing, a helicopter is 2.3 feet long.
The scale on the drawing shows a ratio of 1 foot to 10 feet.
Now, to find the actual length of the helicopter.
Let the actual length of helicopter be 
.
On scale drawing length of helicopter = 2.3 feet.
The scale on the drawing shows a ratio = 1:10.
Now, as ratios are given so by setting proportion we solve it:
<em>By cross multiplying we get:</em>
⇒ 
⇒ 
⇒ 
Therefore, the actual length of the helicopter is 23 feet.
Answer:
The perimeter and area of the square are 56 units and 196 square units, respectively.
Step-by-step explanation:
The inner right triangle represents a 45-45-90 right triangle, which has the feature of a hypotenuse whose length is 
time the length of any of its legs. If the hypotenuse has a measure of 
, then the legs of the triangle have a measure of 
.
Now, we are aware that the side length of the square is twice the length of the leg of the right triangle. Then, side length of the square is 14 units long.
Lastly, we know from Geometry that the perimeter and area of the square are represented by the following expressions:
Perimeter
(1)
Area
(2)
Where 
is the side length of the square.
If we know that 
, then the perimeter and area of the square are, respectively:
The perimeter and area of the square are 56 units and 196 square units, respectively.
#1) A
#2) B
#3) C
#5) A
#7) D
#10) D
#11) D
#14) A
#15) D
#16) A
#19) D
Explanation
#1) If the data set is linear, the slope will be constant throughout the entire data set. For data set A, the slope between the first two points is:
m = (y₂-y₁)/(x₂-x₁) = (1--2)/(3-1) = 3/2
Between the second two points,
m=(4-1)/(5-3) = 3/2
Between the third pairs of points,
m=(7-4)/(7-5) = 3/2
The slope is constant throughout the entire set. The set is also increasing; as x increases, y increases as well.
#2) Substituting 4 for y and 1 for x,
y = (x+1)²
4 = (1+1)² = 2²
9 = (1+2)² = 3²
16 = (1+3)² = 4²
This works for each point, so this is the solution.
#3) Since he runs 10 laps per hour t, this is 10t. Adding the first lap to this, we get y=10t+1.
#5) If a sequence is arithmetic, each term is found by adding a constant (called the common difference) to the previous term. If the common difference is 2, this means that 2 was added each time. This only works for choice A.
#7) For x to vary directly as y, this means that y/x = k; in other words, the quotient of y and x is constant for every point.
#10) The formula for slope is:
m=(y₂-y₁)/(x₂-x₁)
Using the information we're given, we have
3=(d-5)/(4-2)
3=(d-5)/2
Multiply both sides by 2:
3*2 = ((d-5)/2)*2
6 = d-5
Add 5 to both sides:
6+5 = d-5+5
11 = d
#11) Using point slope form,
y-y₁ = m(x-x₁)
y-1 = 3(x--2)
y-1 = 3(x+2)
Using the distributive property,
y-1 = 3*x + 3*2
y-1 = 3x + 6
Add 1 to both sides:
y-1+1 = 3x+6+1
y=3x+7
#14) If two lines are parallel, they have the same slope. The slope of the given equation is 4; the only one with a slope of 4 is A.
#15) If two lines are perpendicular, they have slopes that are negative reciprocals (opposite signs and flipped). The slope of the given equation is 2; this means the slope of the perpendicular line would be -1/2. The only one with this slope is D.
#16) The two equations are not the same, so there are not infinitely many solutions. The variables do not both cancel, so there is at least one solution. This only leaves one solution as the answer.
#19) Using 1 for 7 and 4 for x, we check each equation. The only one that comes out correct is D.
