1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Svetach [21]
3 years ago
7

Draw a quick picture to find the sum or difference

Mathematics
1 answer:
MrRa [10]3 years ago
5 0
For sum u add and for difference you subtract

You might be interested in
Sales tax in Pennsylvania is 6%. Carlos bought a mountain bike that costs $125.50 before tax. What was the cost of the new bike
hoa [83]
I’m pretty sure the answer is 113.03
7 0
3 years ago
Read 2 more answers
A shipping container is in the shape of a right rectangular prism with a length of 1 feet, a width of 9.5 feet, and a height of
Mila [183]

Answer:

11

Step-by-step explanation:

8 0
3 years ago
Use a factor rainbow to determine if 729 is a perfect square. Explain your reasoning.
maksim [4K]

Answer:

729 is a perfect square

Step-by-step explanation:

because 27 * 27 = 729

5 0
3 years ago
Is a credit of $55 negative or positive ?
timofeeve [1]

Answer:

positive

Step-by-step explanation:

3 0
3 years ago
Read 2 more answers
A recent study done by the National Retail Federation found that 2019 back-to-school spending for all US households who have sch
MissTica

Answer:

Step-by-step explanation:

Hello!

The working variable is:

X: Back-to-school expense of a US household with school-aged children.

X~N(μ;σ²)

μ= $697

σ= $120

a. What is the probability that 2019 back-to-school spending for a US household with school-aged children is greater than $893?

Symbolically: P(X>$893)

First, you standardize the probability using Z= (X-μ)/σ ~N(0;1)

P(X>$893)= P(Z>(893-697)/120)= P(Z>1.63)

To resolve this question you have to use the table of cumulative probabilities for the standard normal distribution. These tables accumulate probabilities from the left, symbolically P(Z≤Z₀), so to reach probabilities greater than a Z₀ value you have to subtract the cumulative probability until that value from the maximum probability value 1:

P(Z>1.63)= 1 - P(Z≤1.63)= 1 - 0.94845= 0.05155

b. Provide the Z-score corresponding to the 2019 back-to-school spending of $1,200, and the probability of 2019 back-to-school spending for a household with school-aged children is less than $1,200.

P(X<$1200) = P(Z<(1200-697)/120)= P(Z<4.19)= 1

According to the empirical rule of the normal distribution, 99% of the data is between μ ± 3σ. This, logically, applies to the standard normal distribution. Considering that the distribution's mean is zero and the standard deviation is one, then 99% of the probabilities under the standard normal distribution are within the Z values: -3 and 3, values below -3 will have a probability equal to zero and values above 3 will have probability equal to one.

c. Find Q3 (Third Quartile).

Q3 in the value that marks three-quarters of the distribution, in other words, it has 75% of the distribution below it and 25% above, symbolically:

P(Z≤c)=0.75

In this case, you have to look in the center of the right Z-table (positive) for the probability of 0.75 and then the margins to find the Z-score that belongs to that cumulative probability:

c= 0.674

Now you reverse the standardization to see what value of X belongs to the Q3:

c= (X-μ)/σ

X= (c*σ)+μ

X= (0.674*120)+697= $777.88

d. Find Q1 (First Quartile)

To resolve this you have to follow the same steps as in c., just that this time you'll look for the value that marks the first quarter of the distribution, symbolically:

P(Z≤d)= 0.25

In this case, since the probability is below 0.5 you have to look for the Z value in the left table (negative).

d= -0.674

d= (X-μ)/σ

X= (d*σ)+μ

X= (-0.674*120)+697= $616.12

e. What is the value of the IQR for the distribution of 2019 back-to-school spending for a US household with school-aged children?

IQR= Q3-Q1= $777.88 - $616.12= $161.76

f. Interpret the value of the IQR from question 2e within the context of the problem.

$161.76 represents the distance between 75% of the Back-to-school expense of a US household 25% of the Back-to-school expense of US households.

g. What is the proportion of 2019 back-to-school spending within 1.50 standard deviations of the mean?

"Within 1.50 standard deviations of the mean" can be symbolized as "μ ± 1.5σ" or "μ - 1.5σ≤ Z ≤μ + 1.5σ"

P(μ - 1.5σ≤ Z ≤μ + 1.5σ)

Since the mean is zero and the standard deviation is one:

P(-1.5 ≤ Z ≤ 1.5)= P(Z≤1.5) - P(Z≤-1.5)= 0.933 - 0.067= 0.866

h. What is the 2019 back-to-school spending amount such that only 3% of households with school-age children spend more than this amount?

The "top" 3% means that you are looking for a value of the variable that has above it 0.03 of probability and below it 0.97%, first you look for this value under the standard normal distribution and then you reverse the standardization to reach the corresponding value of the variable:

P(Z>h)= 0.03 ⇒ P(Z≤h)=0.97

h= 1.881

h= (X-μ)/σ

X= (h*σ)+μ

X= ( 1.881*120)+697= $922.72

i. Which US household is more unusual, a US household with back-to-school spending of $600 or a US household with back-to-school spending of $900?

Under this kind of distribution, the "most usual" values are around the center (near the mean) and the "unusual" values will find themselves in the tails of the Gaussian bell.

To check which one is more unusual you have to see their distance with respect to the mean.

(X-μ)/σ

(600-697)/120= -0.8083

(900-697)/120= 1.69

An expense of $900 is more unusual than an expense of $600 (600 is almost the expected expenses)

j. Let's say the Smith family spent $815 on buying school supplies this fall. Provide an interpretation of the Smith family's 2019 back-to-school spending, i.e. what can you say about the percentage of all other US households with school-age children that have higher back-to-school spending than the Smith family?

P(X>$815) = P(Z>(815-697)/120)= P(Z>0.98)

1-P(Z≤0.983)= 0.837

83.7% of the families will have back-to-school expenses of $815 or more.

I hope it helps!

6 0
3 years ago
Other questions:
  • When Roberto got a puppy from the shelter, it weighed 11 pounds. The puppy gained 40% of it's original weight in the first month
    10·2 answers
  • 93 olds bravada 4 .3 liter with a code reading 82 what does this mean ,how to fix
    10·1 answer
  • There are 53 oranges in a box that contains a total of 77 pieces of fruit. How many oranges need to be added so that the box con
    15·1 answer
  • As shown in the image below, triangle ABC is reflected onto its image. А B с С" A Which of the following lines represents the li
    7·1 answer
  • 150% of what number is 105
    13·2 answers
  • F(x) = −16(x − 4)<br> + 255 <br><br> What is the value of f(x) when x = 5?
    7·1 answer
  • Solve: 3,125 = 5^-10 + 3x DONE<br>​
    13·1 answer
  • Amaia walks from her home to the bank, then to the park, and then to get groceries before heading home. The path she travels is
    11·1 answer
  • I NEED HELP ASAP!!! DUE TONIGHT‼️
    14·2 answers
  • Find the gradient of the line segment between the points (-5,-2) and (4,3).
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!