A researcher compares the effectiveness of two different instructional methods for teaching pharmacology. A sample of 63 students using Method 1 produces a testing average of 52.2. A sample of 93 students using Method 2 produces a testing average of 72.3. Assume that the population standard deviation for Method 1 is 15.92, while the population standard deviation for Method 2 is 17.96. Determine the 95% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2.

Answers

Answer 1

Answer:

The 95% confidence interval for the difference between means is (-25.5, -14.7).

Step-by-step explanation:

We have to calculate a 95% confidence interval for the difference between means.

The sample 1 (Method 1), of size n1=63 has a mean of 52.2 and a standard deviation of 15.92.

The sample 2 (Method 2), of size n2=93 has a mean of 72.3 and a standard deviation of 17.96.

The difference between sample means is Md=-20.1.

[tex]M_d=M_1-M_2=52.2-72.3=-20.1[/tex]

The estimated standard error of the difference between means is computed using the formula:

[tex]s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{15.92^2}{63}+\dfrac{17.96^2}{93}}\\\\\\s_{M_d}=\sqrt{4.023+3.468}=\sqrt{7.491}=2.74[/tex]

The critical t-value for a 95% confidence interval is t=1.975.

The margin of error (MOE) can be calculated as:

[tex]MOE=t\cdot s_{M_d}=1.975 \cdot 2.74=5.41[/tex]

Then, the lower and upper bounds of the confidence interval are:

[tex]LL=M_d-t \cdot s_{M_d} = -20.1-5.41=-25.5\\\\UL=M_d+t \cdot s_{M_d} = -20.1+5.41=-14.7[/tex]

The 95% confidence interval for the difference between means is (-25.5, -14.7).


Related Questions

At what point will the graph of the equations 3x +y =7&
y=1 intersect?​

Answers

Answer: The two equations intersect at (2,1)

=======================================================

Work Shown:

Substitute y = 1 into the first equation. Basically we replace every y with 1. From here we solve for x

3x+y = 7

3x+1 = 7

3x+1-1 = 7-1 .... subtracting 1 from both sides

3x = 6

3x/3 = 6/3 .... dividing both sides by 3

x = 2

We have x = 2 pair up with y = 1. The two equations intersect at (2,1)

As a check, plugging (x,y) = (2,1) into the first equation should lead to a true statement

3x+y = 7

3(2)+1 = 7

6+1 = 7

7 = 7 and it does lead to a true statement

The graph is shown below.

A problem requires finding the distance traveled in miles. Which would not be a reasonable​ answer? Justify your response. A.  minus10 B.  1.8 C.  10 and one half D.  50

Answers

Answer:

A.   minus 10,

Step-by-step explanation:

The distance travelled must be positive.

Therefore minus 10 would not be a reasonable answer.

Help me please thank u

Answers

Answer:

160cm

74mm

3.6km is 3600m

Step-by-step explanation:

1. 6 x 100= 160cm

7.4cm x 10 =74mm

3.6 x 1000= 3600m

1.6m in cm
1.6*100
= 160 cm
7.4 cm in mm
= 7.4*10
= 74 mm
3.6 km in m
= 3.6*1000
= 3600m

Does the equation Axequalsb have a solution for each b in set of real numbers RSuperscript 4​? A. ​No, because A has a pivot position in every row. B. ​Yes, because the columns of A span set of real numbers RSuperscript 4. C. ​Yes, because A does not have a pivot position in every row. D. ​No, because the columns of A do not span set of real numbers R

Answers

Answer:

C. Yes, because A does not have a pivot position in every row.

Step-by-step explanation:

The pivot position in the matrix is determined by entries in non zero rows. The pivot position may be in the row or a column. By Invertible Matrix Theorem the equation Axequalsb has non trivial solution. A has fewer pivot positions therefore A is not invertible. Ax will map RSuperscript into real numbers for n times. A has pivot position if left parenthesis bold x right parenthesis.

Sarah kept track of the total number of books she
read. Sarah's graph shows that after 1 week she read a
total of 2 books. After 2 weeks she had read a total of 4
books.
After which week had Sarah read a total of 9 books?

A:8
B:10
C:5
D:6​

Answers

Answer:

A) 8

Step-by-step explanation:

look at the graph where she has 9 books

the ratio of men to women in a village is 12: 25. if there are 120men, (a)how many women are there ?, (b) what is the total number of men to women​

Answers

Answer:

a) 250 women

b) 370 in total

Step-by-step explanation:

Men : Women

12     : 25

120   : 250

a) If there are 120 men that means 12 was multiplied 10 times to get 120 so to get the amount for women we multiply 25 ten times which will give 250.

b) the sum will be 120 + 250 = 370

To the right are the outcomes that are possible when a couple has three children. Assume that boys and girls are equally​ likely, so that the eight simple events are equally likely. Find the probability that when a couple has three​ children, there are exactly 0 girls.

Answers

Answer:

12.5% probability that when a couple has three​ children, there are exactly 0 girls.

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

Possible outcomes:

b for boy, g for girl

g - g - g

g - g - b

g - b - g

g - b - b

b - g - g

b - g - b

b - b - g

b - b - b

8 outcomes, one of which (b - b - b) with exactly 0 girls.

So

1/8 = 0.125

12.5% probability that when a couple has three​ children, there are exactly 0 girls.

The probability that when a couple has three​ children, there are exactly 0 girls is 12.5%

Calculation of the probability:

Here we assume b for boy, g for girl

Now the probability conditions are

g - g - g

g - g - b

g - b - g

g - b - b

b - g - g

b - g - b

b - b - g

b - b - b

There are 8 outcomes, one of which (b - b - b) with exactly 0 girls.

So

[tex]= 1\div 8[/tex]

= 0.125

Learn more about probability here: https://brainly.com/question/24613748

The average amount of water in randomly selected 16-ounce bottles of water is 16.15 ounces with a standard deviation of 0.45 ounces. If a random sample of thirty-five 16-ounce bottles of water are selected, what is the probability that the mean of this sample is less than 15.99 ounces of water? Answer: (round to 4 decimal places)

Answers

Answer:

0.0179 = 1.79% probability that the mean of this sample is less than 15.99 ounces of water.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this question, we have that:

[tex]\mu = 16.15, \sigma = 0.45, n = 35, s = \frac{0.45}{\sqrt{35}} = 0.0761[/tex]

What is the probability that the mean of this sample is less than 15.99 ounces of water?

This is the pvalue of Z when X = 15.99. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{15.99 - 16.15}{0.0761}[/tex]

[tex]Z = -2.1[/tex]

[tex]Z = -2.1[/tex] has a pvalue of 0.0179

0.0179 = 1.79% probability that the mean of this sample is less than 15.99 ounces of water.


The two figures are similar. Write a proportion to find the missing measure. Then find the value of x.

Answers

Answer:

First option is the right choice.

Step-by-step explanation:

x/95 = 15/19

x = 75

Best Regards!

Answer:

Option A

Step-by-step explanation:

Triangle ABC and DEF are similar.

Taking proportion of their sides to find the value of the unknown.

=> x/15 = 95/19

Cross Multiplying

=> 19x = 1425

Dividing both sides by 9

=> x = 75

If the difference between two numbers is 7 and their product is 137 what is the sum of squares if the numbers?

Answers

Answer:

323

Step-by-step explanation:

a-b= 7

ab= 137

a²+b²= ?

---------

Since (a-b)²= a²-2ab +b²

⇒ a²+b²= (a-b)² + 2ab= 7² + 2*137= 323

Five-thirds divided by one-third =

Answers

Answer:

Step-by-step explanation: [tex]\frac{5}{3}[/tex]÷[tex]\frac{1}{3}[/tex] =

(Decimal: 0.555556)

Translate to an algebraic expression.
28 more than d

Answers

Answer: d + 28

Step-by-step explanation:

Answer:

d+28

Step-by-step explanation:

it is easier to remeber that you should always flip the wording so for this on "d" would be first then add the 28

Wayne's service center operates a welding shop. Assume that the arrival of jobs follows a Poisson distribution with 2 jobs arriving in an 8 hour day. The time required to complete a job follows a normal distribution with a mean time of 3.2 hours and a standard deviation of 2 hours.
A. What is the mean service rate in jobs per hour?
B. What is the average number of jobs waiting for service?
C. What is the average time a job waits before the welder can begin working on it?
D. What is the average number of hours between when a job is received and when it is completed?
E. What percentage of the time is Gubser's welder busy?

Answers

Answer:

a) 0.3125 per hour

b) 2.225 hours

c) 8.9 hours

d) 12.1 hours

e) 80%

Step-by-step explanation:

Given that:

mean time = 3.2 hours, standard deviation (σ) = 2 hours

The  mean service rate in jobs per hour (λ) = 2 jobs/ 8 hour = 0.25 job/hour

a) The average number of jobs waiting for service (μ)= 1/ mean time = 1/ 3.2 = 0.3125 per hour

b) The average time a job waits before the welder can begin working on it (L) is given by:

[tex]L=\frac{\lambda^2\sigma^2+(\lambda/\mu)^2}{2(1-\lambda/\mu))} =\frac{0.25^2*0.2^2+(0.25/0.3125)^2}{2(1-0.25/0.3125)}=2.225\ hours[/tex]

c) The average number of hours between when a job is received and when it is completed (Wq) is given as:

[tex]W_q=\frac{L}{\lambda}=2.225/0.25=8.9\ hours[/tex]

d) The average number of hours between when a job is received and when it is completed (W) is given as:

[tex]W=W_q+\frac{1}{\mu} =8.9+\frac{1}{0.3125}=12.1 \ hours[/tex]

e) Percentage of the time is Gubser's welder busy (P) is given as:

[tex]P=\frac{\lambda}{\mu}=0.25/0.3125=0.8=80\%[/tex]

Which of the following is equivalent 8-3x>2(3x-5)

Answers

Answer:

2 >x

Step-by-step explanation:

8-3x>2(3x-5)

distribute

8-3x>6x-10

Add 3x to each side

8+3x-3x>6x+3x -10

8 > 9x-10

Add 10 to each side

8+10 > 9x -10+10

18 > 9x

Divide by 9

18/9 > 9x/9

2 >x

Answer:

[tex]x < 2[/tex]

hope this helps you

brainliest appreciated

good luck! have a nice day!

Step-by-step explanation:

[tex]8 - 3x > 2(3x - 5) \\ 8 - 3x > 6x - 10 \\ 8 + 10 > 3x +6 x \\ 18 > 9x \\ \frac{18}{9} > \frac{9x}{9} \\ 2 > x[/tex]

find the mean of x,2x,3x,4x,5​

Answers

Answer:

Mean = 3x

Step-by-step explanation:

Mean = [tex]\frac{SumOfObservations}{TotalNumberOfObservations}[/tex]

Mean = [tex]\frac{x+2x+3x+4x+5x}{5}[/tex]

Mean = [tex]\frac{15x}{5}[/tex]

Mean = [tex]\frac{15x}{5}[/tex]

Mean = 3x

Hope it will help you.........

Can someone plz help me solved this problem! I’m giving you 10 points! I need help plz help me! Will mark you as brainiest!

Answers

Answer: time = 20 seconds

Step-by-step explanation:

h(t) = -16t² + 316t + 80

The shape of this graph is an upside parabola ∩.  

It lands on the ground when height (h) = 0

Set the equation equal to zero, factor, and solve for t.

0 =  -16t² + 316t + 80

0 =  4t² - 79t - 20              divided both sides by -4

0 = (4t + 1)(t - 20)               factored the equation

t = -1/4      t = 20              Applied Zero Product Property and solved for t

Since we know time cannot be negative, disregard t = -1/4

The only valid solution is: t = 20

In right triangle PQR, What is tan P

Answers

Answer:

c. 3/4

Step-by-step explanation:

tan is opposite over adjacent and based off of the included information its 3/4

Kinda been stuck on this one, someone pls let me know

Answers

Answer:

255

Step-by-step explanation:

use calculator

Answer:

255

Step-by-step explanation:

∑ᵢ₌₁⁸ 2ⁱ⁻¹

Using brute force method:

S = 2⁰ + 2¹ + 2² + 2³ + 2⁴ + 2⁵ + 2⁶ + 2⁷

S = 1 + 2 + 4 + 8 + 16 + 32 + 64 + 128

S = 255

Using formula:

S = a₁ (1 − rⁿ) / (1 − r)

S = 1 (1 − 2⁸) / (1 − 2)

S = 255

A common inhabitant of human intestines is the bacterium Escherichia coli. A cell of this bacterium in a nutrient-broth medium divides into two cells every 20 minutes. The initial population of a culture is 58 cells. (a) Find the relative growth rate. (Assume t is measured in hours.) k = Correct: Your answer is correct. (b) Find an expression for the number of cells after t hours. P(t) = Correct: Your answer is correct. (c) Find the number of cells after 8 hours. 973078528 Correct: Your answer is correct. cells (d) Find the rate of growth after 8 hours. (Round your answer to three decimal places.) billion cells per hour (e) When will the population reach 20,000 cells? (Round your answer to two decimal places.) 2.81 Correct: Your answer is correct. hr

Answers

Answer:

The E. Coli will grow at a rate of approximately 800% an hour.

Taylor Swift wants to know the proportion of her fans who listened to her new single ME! within the first hour of it being released. In order to estimate this, she takes a sample of 150 of her fans and asks them if they listened to the song in this time period. Of the 150 fans, 135 of them (90%) responded that they did listen to the song during this time period. What is the parameter and what is its value

Answers

Answer:

The parameter is the population proportion of fans who  listened to her new single and has an estimated value of 90%.

Step-by-step explanation:

The parameter is a value that corresponds to a population, while an a value that corresponds to a sample is know as statistic.

She takes a sample to estimate, with a point estimate and probably with a confidence interval around this point estimate, the true proportion of fans who listened to her new single.

This is the paramater: the population proportion of fans who listened to her new single.

Its value comes from an estimation based on the sample proportion (point estimate).

The sample proportion is 90%, so we can estimate, as there is no bias, that the population proportion is also 90%.

A probability distribution is a listing of all the outcomes of an experiment and the probability associated with each outcome. The outcomes are mutually exclusive, and the list of outcomes is exhaustive.
1. True
2. False

Answers

Answer:

True.

Step-by-step explanation:

A probability distribution is a listing of all the outcomes of an experiment and the probability associated with each outcome. Probability distribution is associated with the following characteristics or properties;

1. The outcomes are mutually exclusive.

2. The list of outcomes is exhaustive, which simply means that the sum of all probabilities of the outcomes must equal one (1).

3. The probability for a particular value or outcome must be between 0 and 1.

Since a probability distribution gives the likelihood of an outcome or event, a single random variable is divided into two main categories, namely;

I. Probability density functions for continuous variables.

II. Discrete probability distributions for discrete variables.

For example, when a coin is tossed, you can only have a head or tail (H or T).

Also, when you throw a die, the only possible outcome is 1/6 and the total probability for it all must equal to one (1).

If the legs of a right triangle are 10 and 24, then the
hypotenuse is

Answers

26.

Step-by-step explanation:

To figure out the missing side of a right triangle, we will use the Pythagorean theorem. This is...

[tex]a^2+b^2=c^2[/tex]

With this Pythagorean theorem, a and b will always be the legs and the c will always be the hypotenuse, no matter what. Now knowing this, we can plug the legs into the equation.

[tex]10^2+24^2=c^2[/tex]

[tex]100+576=c^2[/tex]

Add the legs together.

[tex]676=c^2[/tex]

Now, since c is squared we will have to find the square root of 676.

[tex]\sqrt{676}[/tex]

= 26

Please answer this correctly

Answers

Answer:

The mode would not change

Step-by-step explanation:

Mode is the frequency of 1 number. In this case, the mode is 3. If we add 8, the frequency of 3 would not change; there would still be 4 3's, and 3 would still have the most of itself.

Please answer this correctly without making mistakes as my work is due today

Answers

Answer:

2

Step-by-step explanation:

Arranging them in ascending order we have the scores as;

[tex]2, 3, 3, 4, 4, 6, 8, 9, 9, 9[/tex]

The median is the average of the 5th and 6th scores.

[tex] \frac{4 + 6}{2} \\ \frac{10}{2} \\ 5[/tex]

The new set of scores become

[tex]2,3,3,4,6,8,9,9,9,9[/tex]

The median is;

[tex] \frac{6 + 8}{2} \\ \frac{14}{2} \\ 7[/tex]

The difference is

[tex]7 - 5 = 2[/tex]

Hope it helps! Vote for brainliest!

Consider the function represented by 9x + 3y = 12 with x as the independent variable. How can this function be written using

function notation?

Fly) = -

f(x) = - 3x + 4

f(x) =

FCV) = -3y+ 4

Answers

Answer:

f(x) = -3x + 4

Step-by-step explanation:

Step 1: Write it in slope-intercept form

9x + 3y = 12

3y = -9x + 12

y = -3x + 4

Step 2: Replace y with f(x)

f(x) = -3x + 4

In math, function f(x) is equal to the variable y.

To express the polynomial 4a^3 + a^2 - 6a^5 + 2a^3 - 4a + 1 in standard form, which terms should be combined?

Answers

Answer:

Step-by-step explanation:

-6a^5+6a^3+a^2-4a+1

Answer:

4a^3 and 2a^3

Step-by-step explanation:

you always start by combining like terms

Which best compares the slope and y-intercepts of the linear functions f and g where f= 1/3 x + 3 and g is shown in the table? X =0,1,2,3 and g(x) =3,6,9,12

Answers

Answer:

different slope same intercept

Step-by-step explanation:

g(x)= 3x+3

this means they both intercept the y axis at 3 but the incline of g is much greater then f since the slope is much larger.Hope this is what you were looking for

A rotary cutter has a radius of 4 centimeters. The hole in the middle of
the cutter has a radius of 0.5 centimeter. What is the area of one side of
the cutter?
10 of 11 QUESTIONS
3.577 cm
15.757 cm?
1671 cm2
13.571 cm2

Answers

Answer:

15.757 im not sure but i came up with that one.

Step-by-step explanation:

78​% of U.S. adults think that political correctness is a problem in America today. You randomly select six U.S. adults and ask them whether they think that political correctness is a problem in America today. The random variable represents the number of U.S. adults who think that political correctness is a problem in America today. Answer the questions below.
1. Find the mean of the binomial distribution ​(Round to the nearest tenth as​ needed.)
2. Find the variance of the binomial distribution. (Round to the nearest tenth as​ needed.)
3. Find the standard deviation of the binomial distribution. (Round to the nearest tenth as​ needed.)
4. Most samples of 6 adults would differ from the mean by no more than nothing. ​(Type integers or decimals rounded to the nearest tenth as​ needed.)

Answers

Answer:

Step-by-step explanation:

Let x be a random variable representing the number of U.S. adults who think that political correctness is a problem in America today. This is a binomial distribution since the outcomes are two ways. The probability of success, p = 78/100 = 0.78

The probability of failure, q would be 1 - p = 1 - 0.78 = 0.22

n = 6

a) Mean = np = 6 × 0.78 = 4.68

b) Variance = npq = 6 × 0.78 × 0.22 = 1.0

c) Standard deviation = √npq = √(6 × 0.78 × 0.22) = 1.0

d) The standard deviation is used to express the spread of the data from the mean. Therefore, most samples of 6 adults would differ from the mean by no more than 1.0

The graph of linear function f passes through the point (1, −9) and has a slope of −3.

Answers

Answer:

Equation of a line y = mx + c

m = slope

Using point (1,-9) and slope -3

y + 9 = -3(x - 1)

y + 9 = -3x + 3

y = -3x + 3 - 9

y = -3x - 6

Hope this helps.

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