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
Elena L [17]
3 years ago
9

A random sample of n measurements was selected from a population with unknown mean μ and known standard deviation σ. Calculate a

95% confidence interval for μ for the given situation. Round to the nearest hundredth when necessary. n = 125, x-bar = 91, σ = 20 Group of answer choices
Mathematics
2 answers:
vivado [14]3 years ago
5 0

Answer:

The 95% confidence interval for μ for the given situation is between 87.49 and 94.51.

Step-by-step explanation:

We have that to find our \alpha level, that is the subtraction of 1 by the confidence interval divided by 2. So:

\alpha = \frac{1-0.95}{2} = 0.025

Now, we have to find z in the Ztable as such z has a pvalue of 1-\alpha.

So it is z with a pvalue of 1-0.025 = 0.975, so z = 1.96

Now, find the margin of error M as such

M = z*\frac{\sigma}{\sqrt{n}}

In which \sigma is the standard deviation of the population and n is the size of the sample.

M = 1.96\frac{20}{\sqrt{125}} = 3.51

The lower end of the interval is the sample mean subtracted by M. So it is 91 - 3.51 = 87.49

The upper end of the interval is the sample mean added to M. So it is 91 + 3.51 = 94.51

The 95% confidence interval for μ for the given situation is between 87.49 and 94.51.

Zanzabum3 years ago
3 0

Answer:

91-1.96\frac{20}{\sqrt{125}}=87.494    

91+1.96\frac{20}{\sqrt{125}}=94.506    

So on this case the 95% confidence interval would be given by (87.494; 94.506). We have 95% of confidence that the true mean is between the limits founded.  

Step-by-step explanation:

Notation

\bar X=91 represent the sample mean

\mu population mean (variable of interest)

\sigma=20 represent the population standard deviation

n=125 represent the sample size  

Confidence interval

The confidence interval for the mean if we know the deviation is given by the following formula:

\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}   (1)

Since the Confidence is 0.95 or 95%, the value of significance is \alpha=0.05 and \alpha/2 =0.025, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that z_{\alpha/2}=1.96

Now we have everything in order to replace into formula (1):

91-1.96\frac{20}{\sqrt{125}}=87.494    

91+1.96\frac{20}{\sqrt{125}}=94.506    

So on this case the 95% confidence interval would be given by (87.494; 94.506). We have 95% of confidence that the true mean is between the limits founded.    

You might be interested in
Explain how we do decimals plus Fractions
Oliga [24]

Answer:

You have to either make the fraction a decimal, or you have the decimal a fraction. Also when making it into a fraction, you should have the same denominator.

Step-by-step explanation:

I hope this helped.

4 0
3 years ago
Read 2 more answers
What is the fraction form of 0.3​
Masteriza [31]

Answer:

3/100

Step-by-step explanation:

Hope this helped!!!

4 0
3 years ago
If a line has a slope of 3/4 then what would be the slope of the parallel to it
AlladinOne [14]

Answer:

it would also be 3/4x (in terms of y=mx+c)

Step-by-step explanation:

parallel lines have the same slope/gradient

6 0
3 years ago
What is a polynomial function
kakasveta [241]
Polynomial is an expression consisting of variables and coefficients, that involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables.
5 0
3 years ago
Read 2 more answers
What would be the answer I need help asap​
Oliga [24]

Answer:

is this weird but in all my years of school I've never learn something like this

7 0
3 years ago
Other questions:
  • PLEASE HELP!!!
    12·2 answers
  • Which pair of lines have the same slopes and y-intercepts?
    7·1 answer
  • (2x-10)(x+3)<br> Simplify each expression
    6·2 answers
  • A woman is now 8 times as old as her son Michael. Two years ago, she was 15 times as old as Michael. Form an equation and solve
    13·2 answers
  • "Fruit Juice May Be Fueling Pudgy Preschoolers, Study Says" is the title of an article that appeared in the San Luis Obispo Trib
    8·1 answer
  • Graph the function d(x) = |x|- 4
    7·1 answer
  • The variable q represents a positive integer. Does 3(59 + 9) + 5q represent a number that is greater than, less than, or equal t
    6·1 answer
  • Plz help guys I need help
    11·1 answer
  • Solve the equation: 8 = 1/3(a+5)
    5·2 answers
  • The sum of twice a number and 4 is 12.
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!