Let x stand for the percentage of an individual student's math test score. 64 students were sampled at a time. The population mean is 78 percent and the population standard deviation is 14 percent. What is the standard deviation of the sampling distribution of sample means?

Answers

Answer 1

Answer:

[tex]\sigma_x= 1.75\%[/tex]

Step-by-step explanation:

Given

[tex]n = 64[/tex]

[tex]\mu = 78\%[/tex]

[tex]\sigma = 14\%[/tex]

Required

The sample standard deviation

This is calculated as:

[tex]\sigma_x= \frac{\sigma}{\sqrt n}[/tex]

This gives:

[tex]\sigma_x= \frac{14\%}{\sqrt {64}}[/tex]

[tex]\sigma_x= \frac{14\%}{8}[/tex]

[tex]\sigma_x= 1.75\%[/tex]


Related Questions

What is the volume of a regular triangular pyramid with an apothem of 2.3ft, a side length of 8ft and a height of 25 feet

Answers

☞ANSWER☜

230FT

Regular tetrahedron

Solve for volume

V≈1.15×107

Use the formula for the volume of a triangular pyramid: V=13Ah , where A = area of the triangular base, and H = height of the pyramid.

Please answer it. I will give brainliest if its correct..

Answers

First find the circumference of the circle:

Circumference = 2 x radius x pi

Circumference = 2 x 4 x 3.14 = 25.12 cm

Now arc ML is 100 degrees.

Multiply the circumference by the arc degree/360 ( 360 is a full circle)

25.12 x 100/360 = 6.98 cm

The answer is 6.98 cm

move two choices to the blanks to correctly complete the sentences.

Answers

Answer:

(A) There should have been 5 outcomes of HT

(B) The experimental probability is greater than the theoretical probability of HT.

Step-by-step explanation:

Given

[tex]S = \{HH,HT,TH,TT\}[/tex] -- Sample Space

[tex]n(S) = 4[/tex] --- Sample Size

Solving (a); theoretical outcome of HT in 20 tosses

First, calculate the theoretical probability of HT

[tex]P(HT) = \frac{n(HT)}{n(S)}[/tex]

[tex]P(HT) = \frac{1}{4}[/tex]

Multiply this by the number of tosses

[tex]P(HT) * n= \frac{1}{4} * 20[/tex]

[tex]P(HT) * n= 5[/tex]

Solving (b); experimental probability of HT

Here, we make use of the table

[tex]P(HT) = \frac{n(HT)}{n(S)}[/tex]

[tex]P(HT) = \frac{6}{20}[/tex]

[tex]P(HT) = 0.30[/tex] ---- Experimental Probability

In (a), the theoretical probability is:

[tex]P(HT) = \frac{1}{4}[/tex]

[tex]P(HT) = 0.25[/tex] ---- Experimental Probability

By comparison;

[tex]0.30 > 0.25[/tex]

Construct an equation for the expression: 3 less than 2 times a number is 7. Show the solution to the equation and prove your solution to be true through your work.

Answers

Answer:

5 x 2 -3 = 7

Step-by-step explanation:

i mean.... thats all

4(x+2) help please.

Answers

Answer:

4x + 8

Step-by-step explanation:

4(x+2)

4*x + 4*2

4x + 8

[tex] \large\sf \leadsto 4(x + 2)[/tex]

[tex] \large\sf \leadsto 4 \times (x + 2)[/tex]

[tex] \huge\sf \leadsto \pmb {4x + 8}[/tex]

What is the surface area of the solid shown below?

Answers

Answer:

[tex]\text{C. }156\:\mathrm{cm^3}[/tex]

Step-by-step explanation:

The surface area of the triangular prism consists of three rectangles and two triangles.

Rectangle One - 5 x 12 = 60 cm^2

Rectangle Two - 4 x 12 = 48 cm^2

Rectangle Three - 3 x 12 = 36 cm^2

Triangles - 2 x 1/2 x 3 x 4 = 12 cm^2

Thus, the total surface area of the solid is [tex]60+48+36+12=\boxed{\text{C. }156\:\mathrm{cm^3}}[/tex]

help me!!!!!!!!!plzzz​

Answers

Answer:

B. 1/3

Step-by-step explanation:

Answer:

1/3

Step-by-step explanation:

add all the values 10+14+6=30 since red is 10 divide 10 by 30 so 10/30 simplifying to 1/3.

a food company can produce 732,291,285crackers per hour. A second food company can produce 732,341,285 crackers per hour.Which company can produce more crackers per hour. explain how you found your answer ​

Answers

Answer:

the second company

Step-by-step explanation:

the second company produces 50,000 more crackers an hour than the first company

The quality-control manager at a compact flourescent light bulb factory wants to test the claim that the mean life of a large shipment of cfls is equal to 6500 hours. the population standard deviation is 500 hours. a random sample of 50 cfls indicates a sample mean life of 6,700 hours and sample standard deviation is 600 hours.
Critical values, where P(Z > Z) - a and P(t >) - a 2016-1282 20.06-1645 20.02 -1.960 10.10. - 1.299 10.06.45 - 1677 foto - 2010 1.115 pt.
a. At the 0.05 level of significance, is there evidence that the mean life is different from 6,500 hours?
b. Compute the p value and interpret its meaning.
c. Construct a 95% confidence interval estimate of the population mean life of the CFLs.
d. Compare the results of (a) and (c). What conclusions do you reach?

Answers

Answer:

a. At the 0.05 level of significance,  there is evidence that the mean life is different from 6,500 hours.

b. The p value= ≈ 0.00480 for z- test which is less than 0.05 and H0 is rejected .

The p value= 0.006913 for t- test which is less than 0.05 and H0 is rejected for 49 degrees of freedom.

c. CI [6583.336 ,6816.336]

d.  The range of CI [6583.336 ,6816.336] tells that the cfls having a different mean life lie in this range.

Step-by-step explanation:

Population mean = u= 6500 hours.

Population standard deviation = σ=500 hours.

Sample size =n= 50

Sample mean =x`=  6,700 hours

Sample standard deviation=s=  600 hours.

Critical values, where P(Z > Z) =∝ and P(t >) =∝

Z(0.10)=1.282  

Z(0.05)=1.645  

Z(0.025)=1.960  

t(0.01)(49)= 1.299

t(0.05)= 1.677  

t(0.025,49)=2.010

Let the null and alternate hypotheses be

H0: u = 6500 against the claim Ha: u ≠ 6500

Applying Z test

Z= x`- u/ s/√n

z= 6700-6500/500/√50

Z= 200/70.7113

z= 2.82=2.82

Applying  t test

t= x`- u /s/√n

t= 6700-6500/600/√50

t= 2.82

a. At the 0.05 level of significance,  there is evidence that the mean life is different from 6,500 hours.

Yes we reject H0  for z- test as it falls in the critical region,at the 0.05 level of significance, z=2.82 > z∝=1.645

For t test  we reject H0   as it falls in the critical region,at the 0.05 level of significance, t=2.82 > t∝=1.677 with n-1 = 50-1 = 49 degrees of freedom.

b. The p value= ≈ 0.00480 for z- test which is less than 0.05 and H0 is rejected .

The p value= 0.006913 for t- test which is less than 0.05 and H0 is rejected for 49 degrees of freedom.

c. The 95 % confidence interval of the population mean life is estimated by

x` ±  z∝/2  (σ/√n )

6700± 1.645 (500/√50)

6700±116.336

6583.336 ,6816.336

d. The range of CI [6583.336 ,6816.336] tells that the cfls having a different mean life lie in this range.

In the figure below, EC || AB. Find the length of EC.

Select the best choice from the answers provided.
A.) 12.5
B.) 18
C.) 25
D.) 39.6

Answers

Answer:

Letter a)

Step-by-step explanation:

quizlet

In a psychology class, 60 students have a mean score of 96.9 on a test. Then 19 more students take the test and their mean score is 71.3.

What is the mean score of all of these students together? Round to one decimal place.
Help please, and thank you! C:

Answers

Answer:83.3

Step-by-step explanation:

At which value in the domain does f(x) = 0?
2
2
4

Answers

Answer:

4

Step-by-step explanation:

A sphere has a volume of 1 cubic foot. What is the approximate diameter of the sphere?

Answers

Answer:

[tex]volume \ of \ sphere = \frac{4}{3} \pi r^3 \\\\1 =\frac{4}{3} \pi r^3\\\\r^ 3 = \frac{3}{4\pi} \\\\r = (\frac{3}{4\pi })^{\frac{1}{3} } \\\\r = 0.62ft\\\\diameter = 2 * 0.62 = 1.24ft[/tex]

Answer:

1.24 ft

Step-by-step explanation:

the volume of sphere = 4/3π.r³ = 1

=> r³ = 3/(4π)= 3/(12.56) = 0.239

r = ³√0.239

r = 0.62

d = 2×0.62 = 1.24 ft

if x varies inversely as y and x=2.5 when y = 40 , find y when x = 2

Answers

Answer:

2.5/40=2/y

2.5y=40x2

2.5y=80

y=80/2.5

y=32

The diagram shows a cylindrical tank.
The radius is 30 cm and the height is 80 cm.

(a) Calculate the area of the base of the tank.

(b) Calculate the volume of the tank in litres.​

Answers

Step-by-step explanation:

a) A=π302=900π CM2 =2,827 CM 2

b) V=Ah=900=72000 π cm 3 = 226,195 cm3

A vehicle owner interested in her vehicle’s fuel economy calculated the gas mileage in miles per gallon (mpg) each time she filled her tank, for several years. Here are the mpg values for a random sample of 20 of these records. Suppose that the standard deviation is known to be σ = 3.5 mpg.

Required:
Find the 95% confidence interval for the mean of gas mileage for this vehicle.

Answers

Answer:

The 95% confidence interval for the mean of gas mileage for this vehicle is (S - 1.53, S + 1.53), in which S is the mean of the sample of 20.

Step-by-step explanation:

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{3.5}{\sqrt{20}} = 1.53[/tex]

The lower end of the interval is the sample mean subtracted by M. So it is S - 1.53.

The upper end of the interval is the sample mean added to M. So it is S + 1.53.

The 95% confidence interval for the mean of gas mileage for this vehicle is (S - 1.53, S + 1.53), in which S is the mean of the sample of 20.

4) To estimate the height of your home, you measure its shadow. The shadow of your home is 5.5 feet.
The shadow of the 10 foot tree has a shadow of 2.5 feet. Find the height of your home. Show all work.

Answers

Answer:

1.375 ft

Step-by-step explanation:

10/2.5 = 4

5.5 / 4 = 1 1.5/4 = 1 3/8 = 1.375 ft

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

Is pop or country your favorite type of music?

Change This into a neutral question

Answers

I like both but I tend to choose pop! :)

A math teacher has a number cube with faces numbered 1 through 6. He will roll the number cube 400 times. Which of the following ranges contains the best prediction for the number of times the number cube will land with a 1 or a 4 on the top face?

A. 30-35

B. 65-70

C. 130-135

D. 265-270

Answers

Answer:

Step-by-step explanation:

B?

PYTHAGOREAN THEOREM !! DONT NEED U TO EXPLAIN JUST GIVE ANSWER DONT HAVE TIME FOR THAT !

Answers

Answer:

√14 or 3.74

Step-by-step explanation:

_________________

Answer:

√14 or 3.74

Step-by-step explanation:

x = 3.74

hellpppppppppspspspspspspsp

Answers

I'd say 13, hope this helps

Step-by-step explanation:

I think it’s 13 sending good vibes your way

A computer technician notes that 40% of computers fail because of the hard drive, 20% fail due to the processor, 15% of problems are with the keyboard, and 5% of problems are due to something else. What is the mean of the number of computers he will work on before seeing his first computer that has failed because of the hard drive?

Since there are four categories, the technician can expect 4 computers until one has failed due to the hard drive.
Since 40% is equivalent to Two-fifths, it is expected that Five-halves = 2.5 computers until one has failed due to the hard drive.
Since the highest percentage of failure is due to the hard drive, the technician can expect that the first computer will have failed due to the hard drive. So the expected value is 1.
Since it is more likely that a computer has failed due to some other issue, the technician can expect the first computer to fail due to some other issue, and the second to fail due to the hard drive. So the expected value is 2

Answers

Answer:

Answer is b

Step-by-step explanation:

You roll 2 dice and flip a coin. What's the probability of getting two 4's and a tails?

Answers

Answer:

2/4

Step-by-step explanation:

Find the measure of the angle, round to the nearest tenth: Sin X = .7547

Answers

SIN(x) = .7547
X = INVERSE-SIN(.7547)
X = 49.0 degrees

Please help me

Find the circumference and the area of this shape

I'll give brainliest ​

Answers

Circumference = 7.5
Area = 176.7
: )^_^^ - ^^o^(*☻-☻*)

PLEASE HELP WILL MARK BRAINLYIST HELP

Answers

Easy it 7/8. Hope this help. Don’t forget to mark me as BRAINLYIST THANKS
Your answer is A. 1/8 gallons/daily
Explanation
1/2 divided by 4 = 1/8

Just trust me, and mark me brainliest ty

Have a nice day!

A={the letters of the word ,HIPPOPOTAMUS}​

Answers

•ω• Hewo fren!

☆☆●◉✿Answer:✿◉●☆☆

The letters of hippopotamus is H-I-P-P-O-P-O-T-A-M-U-S

☆☆●◉✿Step-by-step explanation:✿◉●☆☆

I’m sowy, I didn’t really understand your question... did you want to learn about a hippopotamus? If so, please tell me in the comments I would answer there too!

HOPE I HELPED!  ∧∧

→⇒brainliest please? ∑(OΔO )♥♥︎

!!!MAJOR HELP AND NO LINKS AND IF YOU DONT KNOW BUT YOU STILL ANSWER, I WILL REPORT IF YOU SAY SOMETHING THAT IS NOT AN ANSWER!!!
What is the solution to the equation 7.5 minus X =2.8?
Image above

Answers

Answer: A

Step-by-step explanation:

4.7+2.8 = 7.5

And

7.5 -4.7 = 2.8

What is the surface of the triangluar prism shown below

Answers

Answer: 36 ft^2

Step-by-step explanation: 4x3/2=6. 6x2=12. 3x2=6. 4x2=8. 5x2=10. 12+8+6+10=36

y=x+5
please help me with this problem I'm really struggling to answer the question.​

Answers

Answer:12

Step-by-step explanation:just know i did it and got it right

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