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
Whitepunk [10]
3 years ago
9

A random sample of 49 statistics examinations was taken. the average score, in the sample, was 84 with a variance of 12.25. the

95% confidence interval for the average examination score of the population of the examinations is
Mathematics
1 answer:
tester [92]3 years ago
6 0

Since in this case we are only using the variance of the sample and not the variance of the real population, therefore we use the t statistic. The formula for the confidence interval is:

<span>CI = X ± t * s / sqrt(n)                      ---> 1</span>

Where,

X = the sample mean = 84

t = the t score which is obtained in the standard distribution tables at 95% confidence level

s = sample variance = 12.25

n = number of samples = 49

From the table at 95% confidence interval and degrees of freedom of 48 (DOF = n -1), the value of t is around:

t = 1.68

 

Therefore substituting the given values to equation 1:

CI = 84 ± 1.68 * 12.25 / sqrt(49)

CI = 84 ± 2.94

CI = 81.06, 86.94

 

<span>Therefore at 95% confidence level, the scores is from 81 to 87.</span>

You might be interested in
the Following table shows alexandra's investment options over the course of three years. Her initial investment was $1,000 . wri
Y_Kistochka [10]

The pattern in the given series of amount in the account are in the form of

arithmetic and geometric progression.

  • The function for Option 1 is;  \underline{ f(n) = 1,100 + (n - 1) \cdot 100}
  • The function for Option 2 is; \underline{f(n) = 1,100 \times  1.1^{(n - 1)}}

Reasons:

The given table of values is presented as follows;

\begin{tabular}{c|c|c|c|}Number of years&1&2&3\\Option 1 (Amount in dollars)&1,100&1,200&1,300\\Option 2 (Amount in dollars)&1,100&1,210&1,331\end{array}\right]

In Option 1, the amount in dollars for each year has a common difference of d = 100

The first term, a = 1,100

Therefore;

The Option 1 can be represented as an arithmetic progression , A.P. in the

form, tₙ = a + (n - 1)·d as follows;

For the Option 1, we have;

  • The amount in dollars after <em>n</em> years, \underline{ f(n) = 1,100 + (n - 1) \cdot 100}

For Option 2, it is possible to find;

1,331 ÷ 1,210 = 1,210 ÷ 1,100 = 1.1

Therefore;

The terms in the Option 2 have a common ratio of r = 1.1

The Option 2 is a geometric progression, G.P.

The first term in Option 2 is a = 1,100

Which gives, the nth term, tₙ = a·r⁽ⁿ ⁻ ¹⁾

Therefor;

  • The function for the Option 2 is; \underline{f(n) = 1,100 \times  1.1^{(n - 1)}}

Learn more about arithmetic and geometric progression here:

brainly.com/question/8932895

brainly.com/question/22977503

4 0
2 years ago
Find the volume of the cylinder in terms of pi.
Allushta [10]

Answer:

\large\boxed{V=81\pi\ in^3}

Step-by-step explanation:

The formula of a volume of a cylinder:

V=\pi r^2H

r - radius

H - height

We have r = 3in and H = 9in. Substitue:

V=\pi(3^2)(9)=\pi(9)(9)=81\pi\ in^3

5 0
3 years ago
Question:
mash [69]

Answer:

Question 1: 40 shirts and 40 magizines

Question 2: $4.4

Question 3: 6 gallons

7 0
3 years ago
Read 2 more answers
Which two fractions have a sum of - 7/24
Feliz [49]
The two fractions that added together give you a sum of -7/24 are 1/24+-8/24= -7/24
6 0
3 years ago
A preimage is the the original figure in a transformation.<br> A) True B) False
Kitty [74]
<span>Your answer is True! :) Reason: preimage is the original figure in transformation and </span><span>preimage is the original figure in transformation.</span>
7 0
3 years ago
Read 2 more answers
Other questions:
  • How do u do this and whats the awnser
    13·1 answer
  • Travis has decided to budget his spending money. He can spend no more than $ 143.15 every month. He has also decided to spend 5.
    13·1 answer
  • Consider the tables.
    5·1 answer
  • How do i tell if a relation is a function?
    13·1 answer
  • Is 2/6 greater than 2/8
    8·2 answers
  • Ruby’s market sells smoked meats by the pound. The prices for several different meats are shown in the table.
    9·1 answer
  • Function notation ? G (x)=x-3 ; find g(-6) .. how do I answer this?
    12·1 answer
  • In the triangle below, find the measurements of the unknown angles. a 75 • A. 75 1059 B. 40°. 80° O c. 50, 10° O D. 25°, 50 O E
    10·1 answer
  • ANSWERS
    14·1 answer
  • M∠1 = _°<br><br> •35<br><br> •65<br><br> •50
    12·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!