In a study of academic procrastination, the authors of a paper reported that for a sample of 451 undergraduate students at a midsize public university preparing for a final exam in an introductory psychology course, the mean time spent studying for the exam was 7.74 hours and the standard deviation of study times was 3.10 hours. For purposes of this exercise, assume that it is reasonable to regard this sample as representative of students taking introductory psychology at this university.
(a) Construct a 95% confidence interval to estimate μ, the mean time spent studying for the final exam for students taking introductory psychology at this university. (Round your answers to three decimal places.) TWO VALUES
(b) The paper also gave the following sample statistics for the percentage of study time that occurred in the 24 hours prior to the exam.
n = 451 x = 43.78 s = 21.96
Construct a 90% confidence interval for the mean percentage of study time that occurs in the 24 hours prior to the exam. (Round your answers to three decimal places.)
Answer:
a) The 95% confidence interval to estimate μ is (7.435, 8.045) hours.
b) The 90% confidence interval for the mean percentage of study time that occurs in the 24 hours prior to the exam is (41.079%, 45.481%).
Step-by-step explanation:
Question a:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].
That is z with a pvalue of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.
Now, find the margin of error M as such
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
[tex]M = 1.96\frac{3.3}{\sqrt{451}} = 0.305[/tex]
The lower end of the interval is the sample mean subtracted by M. So it is 7.74 - 0.305 = 7.435 hours
The upper end of the interval is the sample mean added to M. So it is 7.74 + 0.305 = 8.045 hours.
The 95% confidence interval to estimate μ is (7.435, 8.045) hours.
Question b:
90% confidence interval means that [tex]Z = 1.645[/tex]
The margin of error is:
[tex]M = 1.645\frac{21.96}{\sqrt{451}} = 1.701[/tex]
43.78 - 1.701 = 41.079%
43.78 + 1.701 = 45.481%
The 90% confidence interval for the mean percentage of study time that occurs in the 24 hours prior to the exam is (41.079%, 45.481%).
Use the Quadratic Formula to solve the equation. (Enter your answers as a comma-separated list.) 13x^2 +1 = -10
Step-by-step explanation:
The given quadratic equation is :
[tex]13x^2 +1 = -10x\\\\or\\\\13x^2+10x+1=0[/tex]
The formula to solve a quadratic equation is :
[tex]x=\dfrac{-b\pm \sqrt{b^2-4ac} }{2a}[/tex]
Put a = 13, b = 10 and c = 1
So,
[tex]x=\dfrac{-10\pm \sqrt{10^2-4(13)(1)} }{2(13)}\\\\x=-0.118, -0.651[/tex]
Hence, this is the required solution.
help pls pls pls シ
And thanks!
Answer:
the answer the 10.25 u move both decimals over and move it up to the top and divide like normal
Evaluate the indicated limit algebraically. Change the form of the function where necessary. Please write clearly with description of each step, thank you very much.
3x^2+4.5
________
x^2-1.5
lim
x → ∞
Answer:
[tex]\displaystyle \lim_{x\to \infty}\frac{3x^2+4.5}{x^2-1.5}=3[/tex]
Step-by-step explanation:
We want to evaluate the limit:
[tex]\displaystyle \lim_{x\to \infty}\frac{3x^2+4.5}{x^2-1.5}[/tex]
To do so, we can divide everything by x². So:
[tex]=\displaystyle \lim_{x\to \infty}\frac{3+4.5/x^2}{1-1.5/x^2}[/tex]
Now, we can apply direct substitution:
[tex]\Rightarrow \displaystyle \frac{3+4.5/(\infty)^2}{1-1.5/(\infty)^2}[/tex]
Any constant value over infinity tends towards 0. Therefore:
[tex]\displaystyle =\frac{3+0}{1+0}=\frac{3}{1}=3[/tex]
Hence:
[tex]\displaystyle \lim_{x\to \infty}\frac{3x^2+4.5}{x^2-1.5}=3[/tex]
Alternatively, we can simply consider the biggest term of the numerator and the denominator. The term with the strongest influence in the numerator is 3x², and in the denominator it is x². So:
[tex]\displaystyle \Rightarrow \lim_{x\to\infty}\frac{3x^2}{x^2}[/tex]
Simplify:
[tex]\displaystyle =\lim_{x\to\infty}3=3[/tex]
The limit of a constant is simply the constant.
We acquire the same answer.
original price $125 discount ? sale price $81.25
Answer:(125-81.25)/125 = 0.35 = 35%
Step-by-step explanation:
Three triangles are drawn on the same piece of paper such that no two sides are on the same line. What is the maximum number of points of intersection of the three triangles?
Answer:
6
Step-by-step explanation:
Which of the following is false about the figure?
a. m CUD = m VUM
b. M AUV + m DUA = 180
c. m MUC - m MUD = mzCUD
d. m PUD + m VUP = m PUM + m_CUA
Answer:
d.
Step-by-step explanation:
Let's examine each statement:
Option A: m<CUD = m<VUM (CORRECT)
Rationale: vertical angles are congruent to each other.
Option B: m<AUV + m<DUA = 180 (CORRECT)
Rationale: angles on a straight line
Option C: m<MUC - m<MUD = m<CUD (CORRECT)
Rationale:
m<MUC = m<MUD + m<CUD
Subtract m<MUD from each side
m<MUC - m<MUD = m<CUD
Option D is FALSE
Rationale:
m<PUD + m <VUP = 180° (angles on a straight line)
m<PUM + m<CUA ≠ 180°
Therefore,
m<PUD + m<VUP = m<PUM + m<CUA IS FALSE.
Tom read 20 books, 12 magazines, and 18 newspaper articles last year.
Based on this data, what percentage of the material that Tom read is a magazine?
Answer:
Step-by-step explanation:
20 dude hahah
Pay the bill using the fewest possible bills/coins
Answers:
Open the pdf below and youll find what you need. also do the largest bills you can.
Please help me solve this problem and explain the steps
Answer:
1086ft squared
Step-by-step explanation:
What type of angles are <5 and <6?
A. Vertical angles
B. Alternate exterior angles
C. Supplementary angles
D. Alternate interior angles
Answer:
C
Step-by-step explanation:
Supplementary angles because their sum is 180 degrees
Kathy bought 5 pencils for the price of $6.30. Which equation represents r, the cost, in dollars, of each pencil?
A.r=6.30+5
B.r = 6.30÷5
C.r=6.30×5
D.r=6.30−5
9514 1404 393
Answer:
B. r = 6.30÷5
Step-by-step explanation:
The cost per pencil is found by dividing the cost by the number of pencils.
Here, the cost is $6.30 and the number of pencils is 5. Then the cost per pencil (r) is ...
r = 6.30 ÷ 5
what is 5 cm in mm. i need a simple answer. NO LINKS
50 millimeters
keystrokes
The average weekly salary of two employees is $5250. One makes $500 more than the other. Find their salaries.
Answer: thier salaries are $5000 and $5500
Step-by-step explanation:
Let the average weekly salary of one employee be =x
And that of the other employee be = x+500
Such that if thier average of their salaries= $5250
So, their total salary= $5250 x 2=10,500
The equation to solve each employee salary becomes
x+x+500=10,500
2x+500=10,500
2x=10,500-500
2x=10,000
x=10,000 /2
x= first employee salary =$5000
second employee = x+500 =$5500
Question 17
17. Find the scale factor that was used in the dilation shown.
Answer:
We are missing a picture, we can't see the dilation they are referring to. The photo is just showing the answer options, so without the dilation it can't be answered.
Step-by-step explanation:
PLEASE HELP ASAP ???
Answer:
-1
Step-by-step explanation:
What’s the answer to this question ?
Step-by-step explanation:
112=35+d
112-35=d
d=77
hope it helps u
Peter buried a treasure chest on a remote island and is.making a map so he can find it later. One of the key landmarks in the area is a small rectangle hut, 5m by 8m
Rewrite as an exponential equation.
In7 = y
Jenny is dog sitting for 13 dogs. One runs away, and she is not sure which one. There were 3 Labradors (L), 2 Golden Retrievers (G), 3 Dalmatians (D), 4 terriers (T), and 1 bulldog (B) in the original group.
What is the size of the population of dogs that could have run away from Jenny?
1
5
11
13
Answer:
5
Step-by-step explanation:
It is 5 because she originally had 13. There are 5 types of dogs she was dog-sitting. There are 5 possible types of dogs that ran away.
Check the pic please
With steps please
Answer:
Angle BOD = 75⁰
Step-by-step explanation:
Answer attached...
Hope it helps :)
help plz plz plz ill give brain
count the numbers of triangles in the figures
Answer:
A
Step-by-step explanation:
look it carefully.
2- Describe the cross section
The cross-section cut by the plane yields a quadrilateral with length and width equal to the length and width of the face that is parallel to the plane.
Given that £1 = $1.62
b)
a) How much is £650 in $?
b) How much is $405 in £?
Answer:
A) £650 = $1053
B) $405 = £250
Step-by-step explanation:
For a) Since £1 is equal to $1.62 you would just do £650 times 1.62 to get $1053
For b) Since £1 is equal to $1.62 you would do $405 divided by 1.62 to get £250
help please thanks plsss
Answer:
A
area = 256 inches²
side = √256 = 16 inches
B
0.0063 inch = 6.3 × 10^-3
NEED ANSWER ASAP WILL GIVE BRAINLIEST FOR CORRECT ANSWER
Answer:
Slope
Step-by-step explanation:
Hope it helps you in your learning process
Write the log equation as an exponential equation. You do not need to solve for x. log(5x+2)=3
Answer:
So happy you are with brainly
Step-by-step explanation:
34
A figure is translated and then rotated about the origin. Which of the following is
true of the resulting figure and the original figure?
A) The figures are similar.
OB) The figures have different sizes.
OC) The figures are congruent.
D) The figures are neither congruent nor similar.
Answer:
C) The figures are congruent.
Step-by-step explanation:
Given
Translation and rotation on a figure
Required
Select the true option
Rotation and translation are rigid transformation and as such they do not change the size of the figure being transformed.
The implies that, the figure being transformed and the resulting figure will have the same dimension and the same angle measure.
(c) is correct
Answer:
c
Step-by-step explanation:
Amy and Sara's ages are consecutive even integers. The product of their ages is 528. If Sara is
younger, how old is Amy?
Write an equation that can be used to find their ages.
Answer:
24
Step-by-step explanation:
Sara = x age
Amy = x+2 when Sara x = 22 Amy is x + 2 = 24
Product of ages = 528 so............
x(x+2) = 528
x² + 2x - 528 = 0 solve for x I did it graphically first to get x = -24, 22
(x+24) (x-22) = 0
(x+24) = 0 (x-22) = 0
x = -24 x = 22 since you really can't have a negative age