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
lesantik [10]
3 years ago
13

A class survey in a large class for first-year college students asked, “About how many minutes do you study on a typical weeknig

ht?” The mean response of the 463 students was = 118 minutes with a standard deviation of 65 minutes in the population of all first-year students at this university. Create a 99% confidence interval for the mean study time of all first-year students. Assume all necessary assumptions and conditions apply given the large sample size. Interpret your interval in context.
Mathematics
1 answer:
Anika [276]3 years ago
3 0

Answer:  (110.22, 125.78)

Step-by-step explanation:

The confidence interval for the population mean is given by :-

\mu\ \pm z_{\alpha/2}\times\dfrac{\sigma}{\sqrt{n}}

Given : Sample size = 463

\mu=118\text{ minutes}

\sigma=65\text{ minutes}

Significance level : \alpha=1-0.99=0.01

Critical value : z_{\alpha/2}=z_{0.005}=\pm2.576

We assume that the population is normally distributed.

Now, the 90% confidence interval for the population mean will be :-

118\ \pm\ 2.576\times\dfrac{65}{\sqrt{463}} \\\\\approx118\pm7.78=(118-7.78\ ,\ 118+7.78)=(110.22,\ 125.78)

Hence, 99% confidence interval for the mean study time of all first-year students = (110.22, 125.78)

You might be interested in
V + Iwh
madreJ [45]
I think it’s gonna be C. 448
4 0
3 years ago
An explosion causes debris to rise vertically with an initial velocity of 160 feet per second. What is the speed of debris when
lisov135 [29]
The question is asking what v_final is, given that v_initial is at 300 feet. and v_initial is at 0 feet.  
We know there will be a constant downward acceleration of 32.15 ft/s^2.
 Use the following equation: 
 v_final^2 = v_initial^2 + 2ah
 v_final^2 = (160 ft/s)^2 + 2(-32.15 ft/s^2)(300 ft) = 6310 ft^2/s^2
 v_final = (6310 ft^2/s^2)^1/2 = 79.4 ft/s.
5 0
3 years ago
4 Consider the triangle below.
Maurinko [17]
<h2>=>> <u>Solution (part A</u>) :</h2>

Given :

▪︎Triangle AMG is an isosceles triangle.

▪︎Measure of segment AM = (x+1.4) inches

▪︎Measure of segment MG = (2x+0.1) inches

▪︎Measure of segment AG = (3x-0.4) inches

▪︎segment AG is the base of triangle AMG.

Since AG is the base of the isosceles triangle AMG, segment AM and segment MG will be equal.

Which means :

= \tt x + 1.4 = 2x + 0.1

= \tt x + 1.4 - 0.1 = 2x

=  \tt \: x + 1.3 = 2x

= \tt 1.3 = 2x - x

\color{plum} \hookrightarrow  \tt x = 1.3

Thus, the value of x = 1.3

Therefore :

▪︎The value of x = 1.3

<h2>=>> <u>Solution (Part B)</u> :</h2>

We know that :

▪︎The value of x = 1.3

Which means :

The length of the leg AM :

= \tt x + 1.4

= \tt 1.3 + 1.4

\color{plum} \tt leg \: AM= 2.7 \: inches

Thus, the length of the leg AM = 2.7 inches

The length of leg MG :

= \tt 2x + 0.1

=  \tt2 \times 1.3 + 0.1

= \tt 2.6 + 0.1

\color{plum} \tt\: leg \:MG = 2.7 \: inches

Thus, the length of the leg MG = 2.7 inches

Since the measure of the two legs are equal (2.7=2.7), we can conclude that we have found out the correct length of each leg.

Therefore :

▪︎Measure of leg AM = 2.7 inches

▪︎Measure of leg MG = 2.7 inches

<h2>=>> <u>Solution </u><u>(</u><u>part C</u><u>)</u> :</h2>

We know that :

Value of x = 1.3

Then, measure of the base AG :

=  \tt 3x - 0.4

= \tt 3 \times 1.3 - 0.4

= \tt 3.9 - 0.4

\color{plum}\tt \: Base  \: AG = 3.5 \:  inches

Thus, the measure of the base = 3.5 inches

Therefore :

▪︎ the length of base AG = 3.5 inches.

6 0
3 years ago
4.6 x 10 to the 6 power minus 8.3 x 10 to the 5th power
snow_tiger [21]
The answer is 3,770,000
4 0
3 years ago
A jewelry store purchases necklaces for n dollars each. The necklaces are then marked up by 20%, and costumers are charged 5% sa
Aleksandr [31]

Answer:

Step-by-step explanation:

Cost price = $n

Mark up price = selling price- cost price

= (20% × $n)

Selling price = $n + (20% × $n)

Sales tax = 5% × ($n + (20% × $n))

Total cost = selling price + sales tax

Total cost = $n + (20% × $n) + 5% × $n + (20% × $n)

= 1.2 × $n + 0.06 × $n

= 1.26 × $n.

8 0
3 years ago
Other questions:
  • A helicopter hovers 500 feet above a small island. The figure shows that the angle of depression from the helicopter to point p
    12·1 answer
  • please help! A student claims that a figure has rotational symmetry and that the angle of rotational symmetry is 360 degrees. Cr
    11·1 answer
  • Which expression has a value of 35 when p = 7
    12·1 answer
  • Round 5.82-1.76 to the nearest whole number
    8·1 answer
  • orlando is renting a tuxedo for the school formal. he has narrowed his choices down by deciding to wear either navy blue or blac
    10·2 answers
  • The sum of two numbers is 12, and their difference is 17. What are the numbers.
    14·1 answer
  • The area of the cube is shown on the coordinate plane. What is the surface area of the cube?
    12·2 answers
  • Round 7.12568 to the nearest thousandth
    9·2 answers
  • <img src="https://tex.z-dn.net/?f=a%5E%7B2%7D%20%2Aa%5E%7B3%5C%5C%7D" id="TexFormula1" title="a^{2} *a^{3\\}" alt="a^{2} *a^{3\\
    9·2 answers
  • 22x+100=25x+70 <br> Find the X
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!