An educational psychologist wishes to know the mean number of words a third grader can read per minute. She wants to make an estimate at the 85% level of confidence. For a sample of 295 third graders, the mean words per minute read was 26.9. Assume a population standard deviation of 2.7. Construct the confidence interval for the mean number of words a third grader can read per minute. Round your answers to one decimal place

Answers

Answer 1

Answer:

85% level of the confidence interval is

(26.337, 26.662)

Step-by-step explanation:

Explanation:-

Given the size of the sample 'n' = 295

Mean of the sample x⁻ = 26.5

The Standard deviation of the Population = 2.7

85% level of the confidence interval is determined by

[tex](x^{-} - Z_{0.15} \frac{S.D}{\sqrt{n} } , x^{-} + Z_{0.15} \frac{S.D}{\sqrt{n} })[/tex]

Critical value Z₀.₁₅ = 1.036

85% level of the confidence interval is determined by

[tex](x^{-} - Z_{0.15} \frac{S.D}{\sqrt{n} } , x^{-} + Z_{0.15} \frac{S.D}{\sqrt{n} })[/tex]

[tex](26.9 -1.036 \frac{2.7}{\sqrt{295} } , 26.5 + 1.036 \frac{2.7}{\sqrt{295} })[/tex]

( 26.5 - 0.1628 , 26.5+0.1628)

(26.3372,26.6628)


Related Questions

Oliver surveyed 880 of the students in his school about their favorite color. Students
could choose between red and blue. 35% said their favorite color was blue. How many
students' favorite color was red?

Answers

Answer:

572

Step-by-step explanation:

10%=88

5%=44

30%=264

35%=308= favourite colour blue

880-308=572= favourite colour red

A toy jet is 4 inches in length. And it's made using the scale 1 inch = 12.25 feet. What is the length of the actual jet?

Answers

Answer:

It is 49

Step-by-step explanation:

multiply 12.25 by 4  since 1 inch is 12.25 and 4 inches times 12.25 is 49

What are the angles of 1 and 2
Angle BAC and angle FAC are examples of what type of angle pair?
Angle BCE and Angle DCA are examples of what type of angle pair?

Answers

geometry texts refer to an angle with a measure of 180° as a straight angle. In Figure 12 , ∠ BAC is a straight angle.

Step-by-step explanation:

Grapes cost $2.70 per pound. You buy 2.5 pounds of grapes and give the cashier $10. How much change do you receive​

Answers

Answer:

$3.25

Step-by-step explanation:

The grapes costs $2.70 per pound but you're buying 2.5 pounds so take $2.70 x 2.5 = $6.75. Now u just take $10 - $6.75 which equals $3.25 and thats ur answer.

Answer:

You receive 3.25 cash back.

Step-by-step explanation:

2.70 x 2.5 = 6.75

6.75 + ? = 10

A = 3.25

fill in the boxes to show two ways you can find 8+6​

Answers

Answer:

(4+3) + (4+3) and (7-1) + (9-1)

Step-by-step explanation:

You can always break it down in half to make it easier.

Triangle ABC, shown in the diagram below, is an isosceles triangle


If the measure of <ABC is 42.5°, what is the measure of <ABC?​

Answers

Answer:

A. 42.5

Step-by-step explanation:

The triangle shown is an isosceles triangle. An isosceles triangle haas two of its sides and base angles equal. Hence;

<ACB = <ABC (Base angles are equal)

Given

<ACB = 42.5°

Required

<ABC

According to the law above which says <ACB = <ABC , hence <ABC is also equal to 42.5°

if your dogs heart rate is 90 times per minute how many times would it beat in an hour?​

Answers

Answer:5400

Step-by-step explanation: 1 hour is 60 minutes, so 90 * 60 = 5400

Answer:

90 x 60 = 5,400 beats per hour i think

unless the dog dies, then its just sad

Usually Holly leaves home to school at 9:00, however today she left home 20 minutes later. In order to be at school on time she increased her usual speed by 20% and still was at school 15 minutes later than usual. What is her usual time from home to school

Answers

Answer:

Her usual time from home to school is 30 minutes

Step-by-step explanation:

At any point in time;

distance = speed * time

Here, we want to calculate the normal time she spent going from home to school

Let the normal time be x minutes

And the normal speed be t m/min

Today, she increased her speed by 20%

Her speed today will be t + 20/100 * t =

1.2t m/min

Her distance from how to school normally is

xt meters

Now what this means is that, at the increased speed, she was able to get to school 5 minutes earlier

What we are saying is although, she lost 20 minutes initially, she was able to beat down the lateness by 5 minutes

So, the time spent on her increased speed journey is;

(x-5) minutes

At any point in time, the distance will be equal;

Thus, mathematically;

xt = 1.2t(x-5)

xt = 1.2xt - 6t

6t = 1.2xt-xt

6t = 0.2xt

t cancels out

0.2x = 6

x = 6/0.2

x = 30 minutes

Which ratios form a proportion?
A) 4/10 and 10/25
B) 4/9 and 9/4
C) 3/5 and 9/25
D) 4/11 and 6/13

Answers

A) 4/10 and 10/25
These rations form a proportion.

The outdoor temperature is 4 degrees below 0, or

.

-4 0 4


The indoor temperature is 72 degrees above 0, or

.

-72 0 72

Answers

Answer:  The outdoor temperature is 4 degrees below 0 or -4 degrees.

The indoor temperature is 72 degrees above 0 or 72 degrees.

Step-by-step explanation:

We use negative integer to represent loss, below , or withdrawal etc.

On the other hand we use positive integers to show gain , above , deposit etc.

Given statement :   The outdoor temperature is 4 degrees below 0.

So we will represent it by -4 degrees.

The indoor temperature is 72 degrees above 0.

So we will represent it by +72 or 72 degrees.

Answer:

The outdoor temperature is 4 degrees below 0, or

✔ –4

.

The indoor temperature is 72 degrees above 0, or

✔ 72

.

Step-by-step explanation:

Edge instruction

Steps to answerjamie just bought a box

Answers

Answer:

Steps:

Step-by-step explanation:

1: Jamie had the money

2: Jamie went to the store

3: Jamie picked out the box

4: Jamie bought the box

Hope this helped uwu

Garth has a summer job and earns $9.32 per hour. One week, he works 16 34 hours. He deposits $150 in a bank and decides to use the rest of the money to buy raffle tickets. Each raffle ticket costs $0.50. How many raffle tickets can Garth buy?

Answers

Answer:

12 tickets

Step-by-step explanation:

Earning = $9.32 per hourWork hours = 16 3/4 = 16.75

Earning in week:

$9.32*16.75 = $156.11

Remaining money after he deposits $150:

$156.11 - $150 = $6.11

How many raffle tickets can be bought:

$6.11/$0.50 = 12 and $0.11 remains

Answer:

12 tickets

Step-by-step explanation:

PLEASE HELP! GIVEE ME THE 14 ANSWERS FOR THIS FOR BRAINLIEST

Answers

Answer:

Step-by-step explanation:

oh boy

1) 9 < 16

2) -4 < 5

3) 18 > -19

4) -38 < -16

5) 6 > 4

6) -14 > -25

7) -45 > -55

8) -2 > -10

9) -4, -1, 1, 3, 6

10) -15, -13, -5, 8

11) -9, -6, -5, -1, 0

12) -4, -2, 1, 3

13) -10, -9, 7, 8, 11

14) -33, -25, -14, -4, 7

hope this helps <3

What is the value of this expression 3x[(7+8)x2+6]

Answers

Answer:

96 or 108

Step-by-step explanatio

The lengths of a professor's classes has a continuous uniform distribution between 49.29 min and 55.55 min. If one such class is randomly selected, find P54

Answers

Answer:

52.6704

Step-by-step explanation:

The lengths of a professor's classes has a continuous uniform distribution between 49.29 min and 55.55 min

Let x = 49.29, y=55.55

Percentile(P) = 54/100 = 0.54

P54 = x+(y-x)p

P54 = 49.29 + (55.55-49.29)*0.54

P54 = 49.29 + 6.26*0.54

P54 = 49.29 + 3.3804

P54 = 52.6704

What is the solution for x divided by 9>4

Answers

Answer:

Step-by-step explanation:

x > 36

Answer:

.

Step-by-step explanation:

.

The areas of two similar triangles are 18cm^2 and 8cm^2. One of the sides of the first triangle is 4.5cm. What is the length of the corresponding side of the other triangle? Please answer ASAP!!! Thank you!!!

Answers

Answer:

3 cm

Step-by-step explanation:

The area is the product of two dimensions, therefore the scale factor is:

A/A' = (b*r*h*r)/(b*h) = r²r² = 18/8r = √9/4 = 3/2 = 1.5

The length of the corresponding side will be:

a/a' = ra' = a/ra' = 4.5 / 1.5 a' = 3 cm

Need help 25 points image below

Answers

Answer:

Brooks answer is incorrect because he should not shift the brackets to other numbers. First he should distribute number 2 to be multiplied to each number inside the bracket

Can anyone help me with this thank you :))

Answers

Answer:17

Step-by-step explanation:

5w + 2

5(3) + 2

15 + 2

17

Answer is = 17
5w+2
5(3)+2
5x3=15+2=17

95°
60°
29
o
X =
Plzzzz I need this

Answers

Answer:

x=95

Step-by-step explanation:

They are vertical angles

a manufacturer says that the diagonal measurement of a laptop computer is 16 inches. Find the relative error of this measurement to the nearest tenth.

A. 0.6%

B.1.6%

C.3.1%

D.6.3%

Answers

Answer:

As this is incomplete, it lacks the value of actual error.

Here, we do not know the actual value. so let's assume it is 1 inch

Relative Error = 6.25 % ≈ 6.3% = D

Step-by-step explanation:

As this is incomplete, it lacks the value of actual error.

We are asked to calculate the relative of the measurement.

Relative error formula = Actual error/Measurement x 100

Here, we do not know the actual value. so let's assume it is 1 inch

Actual value = 1 inch

Measurement = 16 inch

Relative Error = 1/16 x 100

Relative Error = 6.25 % ≈ 6.3% = D

D. 6.3%

A publisher reports that 55% of their readers own a laptop. A marketing executive wants to test the claim that the percentage is actually different from the reported percentage. A random sample of 280 found that 51% of the readers owned a laptop. Make the decision to reject or fail to reject the null hypothesis at the 0.05 level.

Answers

Answer:

We fail to reject the null hypothesis, we accept H₀

Step-by-step explanation:

Population proportion        p₀   =  55 %    p₀   =  0,55

Sample  size         n  =  280

Sample mean     p =  51 %            p =  0,51       q = 0,49

n*p   and  n*q   are both bigger than 10 therefore we can approximate the binomial distribution to a normal distribution

Test  Hypothesis

Null Hypothesis                             H₀                   p   =  p₀

Alternative Hypothesis                Hₐ                    p   ≠  p₀

Significance level is  α  = 0,05    but we have a two-tail test then

α/2  =  0,025

z(c)  =  - 1,96

Computing  z(s)

z(s)  =  ( p - p₀ ) / √(p*q)/n

z(s)  =  ( 0,51 - 0,55 ) / √(0,51*0,49)/280

z(s)  =  - 0,04 * 16,73 / 0,5

z(s)  =  -  1,34

Comparing

z(s)   and z(c)

- 1,34    <    - 1,96

| z(s) | < | z(c)|

Then z(s) is in the acceptance region,  we accept H₀

Find the missing exponent in each expression

Answers

Answer:

See below.

Step-by-step explanation:

Multiplying terms with exponents make the exponents add together.

13.) x² · x⁵ = x⁷

14.) b⁵ ·  b³ = b⁸

15.) y⁴ · y⁷ = y¹¹

16.) m⁴ · m¹ = m⁵

PLEASE I REALLY NEED YOUR HELPPPP!!!!!!!!!!!!1

Answers

Answer:

Step-by-step explanation:

11+20+4=35

11/35 red

20/35 or 4/7 yellow

4/35 blue

im stuck on the second sorry

Step-by-step explanation:

wjwjajwjwjjajawkakkwwmwmw..wllaa

If you take out a loan for $4,000 and you will owe $4,920 after 2 years, what is the rate of simple interest? Express your answer as a percentage rounded to the nearest tenth of a percent if necessary, but do not include the percent sign.

Answers

Answer:

11.5

Step-by-step explanation:

Answer:

11.5

Step-by-step explanation:

you have to use this equation to solve it [r = (1/t)(A/P - 1)] and basically just plug the numbers in to get 11.5. (you could also use one of those online calculators)

r = (1/2)((4920/4000) - 1) = 0.115

r = 0.115

An air conditioning system can circulate 420 cubic feet of air per minute. How many cubic yards of air can it circulate per​ minute?

Answers

Answer:

15.5556 cubic yards

Step-by-step explanation:

A yard is equal to three feet.  Divide the volume value by 27 (3 cubed).


Complete the ratio table for Car A.

Answers

Answer:

The answer for miles driven is 100 for the first blank, 400 for the second blank, and 600 for the third blank. As you can see, that is how the pattern goes. The blank for Gallons of gas one is 12, and the blank for gallons of gas two is 20.

Step-by-step explanation:

Help please...................

Answers

Answer:

7 1/8

Step-by-step explanation:

4 + 2 = 6

6/8 + 3/8 = 9/8 or 1 1/8

1 1/8 + 6 = 7 1/8

Find all solutions to the equation. cos x = - 1/2

Answers

Answer:

[tex]x = 2\pi /3 + 2\pi n\\x= 4\pi /3 + 2\pi n[/tex]

Step-by-step explanation:

Radian: x = 2\pi /3 + 2\pi n\\x= 4\pi /3 + 2\pi n

Degree:  x = 120 + 360n , x = 240 + 360n

(13 + 4i) + n = 0
What is n?

Answers

Answer:

-13-4i

Step-by-step explanation:

(13+4i)+n=0

n=-(13+4i)

n=-13-4i

answer:
n = -13-4i
explanation:
first you move the constants to the right and then you remove the opposites and
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