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
marishachu [46]
3 years ago
13

a researcher wants to know the typing speed of the students in a large vocational school. the population standard deviation is p

reviously known to be 2.5 minutes. if the researcher wants a margin of error of 0.50 minute and an alpha level of 0.05, what should be the sample size?
Mathematics
1 answer:
tester [92]3 years ago
4 0
1) It is known that a laboratory task takes the average person 2.5 seconds. A researcher was interested in whether older people are slower (take longer) on this task. The researcher tested 30 randomly selected 80-year-olds. Their mean time was 2.7 seconds, with an estimated population standard deviation of 1.4 seconds. What should the researcher conclude (use the .05 level)? a. /2 Identify the populations involved: population 1 = _____________________________________________________________________ population 2 = _____________________________________________________________________ b. /2 State the research and null hypothesis: Research Hypothesis = _____________________________________________________________ Null Hypothesis = _________________________________________________________________ c. /6 Determine the characteristics of the comparison distribution (hint: it is a distribution of means): mean of the distribution of means = degrees of freedom = estimated population variance = estimated population standard deviation = variance of the distribution of means = standard deviation of distribution of means = d. /1 Cutoff sample score on the comparison distribution at which we’ll reject H0 (hint: 1 or 2 tails?) = e. /1 Determine your sample’s score on the comparison distribution = f. /1 Accept or reject the null hypothesis? g. /4 Sketch the distributions involved:
You might be interested in
The formula for the perimeter of a rectangle is p=2l 2w.
IRINA_888 [86]
I think the answer is c i’m not sure
5 0
3 years ago
Determine whether the following are subspaces of R2×2 : (a) Thesetofall2×2diagonalmatrices (b) The set of all 2 × 2 triangular m
Mrrafil [7]

A vector space V is a subspace of a vector space W if

  • V is non-empty,
  • for any two vectors v_1,v_2\inV we have v_1+v_2\in V, and
  • for any scalar k and v\in V we have kv\in V.

It's easy to show the first condition is met by all the sets in parts (a-g).

(a) is a subspace of \Bbb R^{2\times2} because adding any 2x2 diagonal matrices together, or multiplying one by some scalar, gives another diagonal matrix.

(b) and (c) are also subspaces for the same reasons.

(d) is not a subspace because \Bbb R^{2\times2} because this set of matrices does not contain the zero matrix.

(e), however, is a subspace. Any linear combination of matrices in this set always yields a matrix with 0 in row 1, column 1 entry.

(f) is a subspace. A symmetric matrix is one of the form

\begin{bmatrix}a&b\\b&c\end{bmatrix}

Adding two symmetric matrices gives another symmetric matrix:

\begin{bmatrix}a_1&b_1\\b_1&c_1\end{bmatrix}+\begin{bmatrix}a_2&b_2\\b_2&c_2\end{bmatrix}=\begin{bmatrix}a_1+a_2&b_1+b_2\\b_1+b_2&c_1+c_2\end{bmatrix}

(g) is not a subspace. Consider the matrices

\begin{bmatrix}1&0\\0&0\end{bmatrix},\begin{bmatrix}0&0\\0&1\end{bmatrix}

Both matrices have determinant 0, but their sum is the identity matrix with determinant 1.

4 0
4 years ago
A Christmas gift is tied with ribbon the bow requires 47cm of ribbon, what is the total length of the ribbon in cm?
Sophie [7]

The complete question is as follows: A Christmas gift is tied with ribbon the bow requires 47cm of ribbon, what is the total length of the ribbon in cm?

Answer: The total length of the ribbon is 177 cm.

Step-by-step explanation:

As there are 4 sides of the rectangular box and 20 cm of ribbon is on each side. This means that a total of 4 \times 20 cm = 80 cm is there on the top and bottom.

Hence, length of ribbon attached at the left and right side of the box is as follows.

2.5 \times 10 cm = 25 cm\\2 \times 25 cm = 50 cm

This means that on both left and right side a total of 50 cm is there.

Therefore, total length of ribbon is as follows.

Total length = 47 cm + 50 cm + 80 cm = 177 cm

Thus, we can conclude that the total length of the ribbon is 177 cm.

7 0
3 years ago
The height of a ball thrown directly up with a velocity of 10 feet per second from a initial height of of 100 feet is given by t
Nutka1998 [239]
The ball will hit the ground when h(t)=0 so:

-16t^2+10t+100=0

Using the quadratic equation:

t=(-10±√6500)/-32, and since t>0

t≈2.8 seconds (to nearest tenth of a second)


5 0
3 years ago
Read 2 more answers
Please answer it is related to square root​
Lubov Fominskaja [6]

Answer:

Step-by-step explanation:

2\sqrt{8}+3\sqrt{50}=2\sqrt{2*2*2} + 3\sqrt{5*5*2}\\\\= 2*2\sqrt{2}+3*5\sqrt{2}\\\\=4\sqrt{2}+15\sqrt{2}\\\\= 19\sqrt{2}

3\sqrt{12}+4\sqrt{27}=3\sqrt{2*2*3}+4\sqrt{3*3*3}\\\\=3*2\sqrt{3}+4*3\sqrt{3}\\\\=6\sqrt{3}+12\sqrt{3}\\\\=(6+12)\sqrt{3}\\\\= 18\sqrt{3}

6 0
3 years ago
Other questions:
  • The legs of a right triangle measure 14 and 25 what is the measure of the angle opposite to the shortest side
    6·1 answer
  • What is the image of point (4,3) if the rotation is -90
    10·1 answer
  • Write the sum of the numbers as the product of their GCF and another sum 56 + 64
    12·1 answer
  • Henry and walter open savings accounts at the same time. henry invests $6,500 at 4.54% simple interest, and walter invests $7,10
    6·2 answers
  • Graph
    13·1 answer
  • Can someone tell/show me how to find the volume of this?
    12·1 answer
  • A classroom has 14 blue chairs, 5 green chairs and 11 red chairs. If a chair is selected from the classroom at random, which col
    12·2 answers
  • -4y - 11x = 36 -10y - 10x = 20 ​
    11·1 answer
  • Find a solution to the linear equation y=6x−18 by filling in the boxes with a valid value of x and y.
    10·1 answer
  • I need help with question b
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!