Answer:
1 1/4
Step-by-step explanation:
Researchers investigated whether providing a fancy, foil-wrapped piece of chocolate with the dinner bill would lead to higher tips than not providing such a treat. Sixty-four dinner parties at a restaurant in Ithaca, NY were randomly assigned to receive such a piece of chocolate or not with their dinner bill. Of the 32 parties who received the chocolate, the average tip (as a percentage of the bill) was 17.84%, with a standard deviation of 3.06%. Of the 32 parties who did not receive the chocolate, the average tip (as a percentage of the bill) was 15.06%, with a standard deviation of 1.89%. Determine a 96% confidence interval for the size of the difference in average tips between the two groups
Answer:
The 96% confidence interval for the size of the difference in average tips between the two groups is (1.47%, 4.09%).
Step-by-step explanation:
Before building the confidence interval, we need to understand the central limit theorem and subtraction of normal variables.
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.
Subtraction of normal variables:
When we subtract normal variables, the mean is the subtraction of the means while the standard deciation is the square root of the sum of the variances.
Of the 32 parties who received the chocolate, the average tip (as a percentage of the bill) was 17.84%, with a standard deviation of 3.06%.
This means that:
[tex]\mu_{C} = 17.84, s_{C} = \frac{3.06}{\sqrt{32}} = 0.541[/tex]
Of the 32 parties who did not receive the chocolate, the average tip (as a percentage of the bill) was 15.06%, with a standard deviation of 1.89%.
This means that:
[tex]\mu_{NC} = 15.06, s_{NC} = \frac{1.89}{\sqrt{32}} = 0.3341[/tex]
Difference in average tips
The distribution has mean:
[tex]\mu = \mu_{C} - \mu_{NC} = 17.84 - 15.06 = 2.78[/tex]
Standard deviation:
[tex]s = \sqrt{s_{C}^2 + s_{NC}^2} = \sqrt{0.541^2 + 0.3341^2} = 0.6358[/tex]
96% confidence interval
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 - 0.96}{2} = 0.02[/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 - 0.02 = 0.98[/tex], so Z = 2.054.
Now, find the margin of error M as such
[tex]M = zs[/tex]
[tex]M = 2.054*0.6358 = 1.31[/tex]
The lower end of the interval is the sample mean subtracted by M. So it is 2.78% - 1.31% = 1.47%
The upper end of the interval is the sample mean added to M. So it is 2.78% + 1.31% = 4.09%
The 96% confidence interval for the size of the difference in average tips between the two groups is (1.47%, 4.09%).
Seventy million pounds of trout are grown in the U.S. every year. Farm-raised trout contain an average of 32 grams of fat per pound, with a standard deviation of 7.5 grams of fat per pound. A random sample of 34 farm-raised trout is selected. The mean fat content for the sample is 30.5 grams per pound. Find the probability of observing a sample mean of 30.5 grams of fat per pound or less in a random sample of 34 farm-raised trout.
Answer:
0.121 = 12.1% probability of observing a sample mean of 30.5 grams of fat per pound or less in a random sample of 34 farm-raised trout.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score 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 p-value, 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.
Farm-raised trout contain an average of 32 grams of fat per pound, with a standard deviation of 7.5 grams of fat per pound.
This means that [tex]\mu = 32, \sigma = 7.5[/tex]
Sample of 34:
This means that [tex]n = 34, s = \frac{7.5}{\sqrt{34}} = 1.2862[/tex]
Find the probability of observing a sample mean of 30.5 grams of fat per pound or less in a random sample of 34 farm-raised trout.
This is the pvalue of Z when X = 30.5. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{30.5 - 32}{1.2862}[/tex]
[tex]Z = -1.17[/tex]
[tex]Z = -1.17[/tex] has a pvalue of 0.121
0.121 = 12.1% probability of observing a sample mean of 30.5 grams of fat per pound or less in a random sample of 34 farm-raised trout.
Free brainlest! Just answer this....... WHAT IS BETTER PS4 OR Xbox if you get it right you can have it!
Answer:
Depends
Step-by-step explanation:
PS4 has a better gaming system and better games (Spiderman example)
But Xbox has the better controller. I think Xbox is better I prefer it but it doesn't really matter.
Consider the figure below with circles R, C, and D below, where circle R and circle D are
congruent. If RA = 42 and CE = 32, then answer the questions below.
R
D
424
E
32
с
Part A: Determine CA + ED.
Part B: Determine the combined circumference of all three circles.
Answer:
a) CA + ED = 74
Step-by-step explanation:
The complete question is attached in the image
Solution
Here the two circles R and D are congruent and thus their radius will be equal
Hence, RA (radius of circle R ) = DE (radius of circle D)
Hence, CA + ED = CA + 42
Also, RC = CD
CA = CE + RA = 32
So, CA + EO = 32 +42 = 74
On the number line, plot and label all numbers with an absolute value of 32. Where did you place the points?
Answer:
on 32 and -32
Step-by-step explanation:
how can you use the multiplicative inverse to solve division problems?
(best answer gets brainliest)
Answer:
Hello, the multiplicative inverse is just another name for reciprocal. You can use this type of method when dividing fractions like:
1/2/3/5
You use the method known as kfc, keep, flip, change like this:
1/2 x 5/3
Notice how 1/2 is kept the same, the division sign is now a multiplying sign, and 3/5 is flipped.
And then you just answer it from there and you get 5/6
Step-by-step explanation:
I hope this helped you!
Unit 11: Volume & Surface Area Homework 3: Area of Composite Figures find the area of each figure. found to the nearest hundredth where necessary.
Answer: 7.5
Step-by-step explanation:
A1=1/2pir^2 A2=1/2pir^2
1/2(121pi) 1/2(16pi)
5.5 2
The area of a composite shape is the sum of the areas of its individual shapes
The area of the composite shape is 215.20 square feet.
From the figures, we have the following shapes
A semicircle with a diameter of 22 ftA semicircle with a diameter of 8 ft (i.e. 30ft - 22ft)The area (A) of a semicircle is:
[tex]\mathbf{A = \frac{\pi d^2}{8}}[/tex]
So, the area of the composite shape is:
[tex]\mathbf{A = \frac{\pi (d_1^2 + d_2^2)}{8}}[/tex]
This gives
[tex]\mathbf{A = \frac{\pi (22^2 + 8^2)}{8}}[/tex]
[tex]\mathbf{A = \frac{\pi (548)}{8}}[/tex]
[tex]\mathbf{A = 68.5\pi}[/tex]
[tex]\mathbf{A = 215.20}[/tex]
Hence, the area of the composite shape is 215.20 square feet.
Read more about areas at:
https://brainly.com/question/16741417
When building a house, the number of days required to build is inversely proportional
to with the number of workers. One house was built in 132 days by 4 workers. How
many days would it take to build a similar house with 16 workers?
Answer: 33
Step-by-step explanation:
FOR BRANLIEST PLEASE HELP!!
Answer:
75°
Step-by-step explanation:
<4=<105 because they are corresponding angles.
Angles along a straight line add to 180°, so <1+<4=180. Therefore <1=180-105=75°
Determine the average percent of change from 1960–2000
1960 1970 1980 1990 2000
$0.25 $0.36 $1.19 $1.35 $1.26
show your work
Answer:
1970 +46%
1980 +232%
1990 +14%
2000 -8%
Step-by-step explanation:
what’s the domain of this relation?
Answer:
there is nothing here but thanks for the points
Step-by-step explanation:
Have a great rest of your day/night!
Hows your day i just want to know: Who are your top 3 favorite rappers? And give me your or one of your favorite songs by each one?
Answer:
um mm
Brent fayiyz
all his songs
and ummm
5x +60/x -15x +15/x-20
Answer:
5x-60=x - solution,..........
Answer:
Answer:
5x +60/x -15x +15/x-20
60/x+15/x-15x+5x-20
75/x-10x-20
is your answer
combined liked terms by adding and subtracting.
The area of a square is 54 cm. What
is the length of each side of the
square?
A. between 8cm and 9cm
B. between 5cm and 6cm
C. between 6cm and 7cm
D. between 7cm and 8 cm
A store stocked 150 cans of popcorn for a weekend sale. That Weekend, 99 of the cans sold. What percentage of cans of popcorn stocked were unsold that weekend?
Answer:
34%
Step-by-step explanation:
99/150 = 0.66
1.00 - 0.66 = 0.34
34%
Answer:There is 48% of cans
HELP ME PLEASE!!! No links
Answer:
H 60
Step-by-step explanation:
You would need to find out what you would multiply times 0.5 to get 30. Then to get that answer just divide 30 by 0.5. which is 60
A sandbox is shaped like a regular hexagon. The side lengths are 3 ft and the apothem 3√3 ft.
What is the area of the hexagonal sandbox?
Enter your answer as a decimal to the nearest hundredth.
area = __ft²
Answer:
46.77ft^2
Step-by-step explanation:
What is the length from Alaska to Chicago times 5 divided by 3?
Answer:
14302 miles
Step-by-step explanation:
from alaska to chicago it is 2861 mi.
2861 times 5
that divdied by three is 14302
I NEED HELP LIKE ASAP PLS!!!!
Answer:
formula 3 only
Step-by-step explanation:
formula for the are of a circle is [tex]A=\pi r^{2}[/tex]
the other 2 formulas are the ones for circumference
Find the mean absolute deviation of the set of data. Round your answer to two
decimal places.
3, 1, 5, 4, 8,6
Answer:
4.5 is the mean/average
Step-by-step explanation:
3+1+5+4+8+6=27
27 divided by 6 = 4.5
9 cm
4 cm
1
14 cm
5 cm
Answer:
this is D
Step-by-step explanation:
A rectangular lawn measuring 24 feet by 16 feet is surrounded by a flower bed of uniform width. The combined area of the lawn and the flower bed is 660 square feet. What is the width of the flower bed?
Answer:
6 feet
Step-by-step explanation:
(24+x)(16+x)=660
384+24x+16x+x²=660
x²+40x-276=0
x`= 6
x```= -46......no serve
Answer......is 6 feet
The width of the flower bed is 6 feet.
What is the area of a rectangle?The area of any shape is the number of unit squares that fit inside it. Here "unit" refers to 1, and a unit square is a square with sides of 1 unit.So the area of a rectangle is the number of unit squares within the bounds of the rectangle.Alternatively, the space occupied around this shape is called the area of the rectangle.The area occupied by the bounding rectangle is called the rectangular area.Area can be defined as the amount of space covered by a plane of a particular shape.It is measured in "number" of square units (square centimeters, square inches, square feet, etc.).The area of a rectangle is the number of unit squares that fit in the rectangle.Examples of rectangles are flat surfaces such as laptop monitors, chalkboards, and canvases.6 feet is the width of the flower bed.
(24+x)(16+x)=660
384+24x+16x+x²=660
x²+40x-276=0
x`= 6
x```= -46 which cannot be the case, therefore 6 feet is the width of the flower bed.
To learn more about area, refer
brainly.com/question/25292087
#SPJ2
Please Classify ∠1 and ∠2 using all names that apply
Answer:
if the sum of the two angles is 90°,then they are said to be complementary angles.Sean and Hope are going bowling. For each person, a game costs $4.25. Shoe rentals are $3.00. Sean gives the clerk $20 for their admission and shoe rental. How much change should he receive? *
1 point
$12.75
$5.50
$9.75
$14.50
PLZ HELPPP ME NEED IT BY TODAYYYYYYYYYY!!!!!!!!!!!!!
Answer:
The answer is 5.50.
Step-by-step explanation:
First, you do 4.25+3.00=7.25
Second, 20-7.25=12.75
but read the beggining again it says sean AND hope so repeat the step again.
First, you do 4.25+3.00=7.25
Second, 20-14.50=5.50
A farmer sells 6.5 kilograms of apples and pears at the farmer's market.
3
4
of this weight is apples, and the rest is pears. How many kilograms of pears did she sell at the farmer's market?
Answer:
1.625 kg
Step-by-step explanation:
Subjects with pre-existing cardiovascular symptoms who were receiving subitramine, an appetite suppressant, were found to be at increased risk of cardiovascular events while taking the drug. The study included 9804 overweight or obese subjects with pre-existing cardiovascular disease and/or type 2 diabetes. The subjects were randomly assigned to subitramine (4905 subjects) or a placebo (4899 subjects) in a double-blind fashion. The primary outcome measured was the occurrence of any of the following events: nonfatal myocardial infarction or stroke, resuscitation after cardiac arrest, or cardiovascular death. The primary outcome was observed in 561 subjects in the subitramine group and 495 subjects in the placebo group. Do the data give good reason to think that there is a difference between the proportions of treatment and placebo subjects who experienced the primary outcome
I WILL GUVE BRAINERLEST AND A LIKE
Jack needs to replace some flooring in
his house.
Answer:
B
Step-by-step explanation:
i think
five million ninety thousand thirty nine
Answer:
5,090,039
Step-by-step explanation:
Are you trying to number it out?
Answer:
5,090,039
Step-by-step explanation:
Just separate them, do them one at a time and add them all together
5,000,000
90,000
+ 039
___________
Hope this helps
~R3V0
Herons formula triangle is
Answer:
Heron's formula (sometimes called Hero's formula), named after Hero of Alexandria, gives the area of a triangle when the length of all three sides are known. Unlike other triangle area formulae, there is no need to calculate angles or other distances in the triangle first.
algebraically find the inverse of a function
9514 1404 393
Answer:
1) f⁻¹(x) = 6 ± 2√(x -1)
3) y = (x +4)² -2
5) y = (x -4)³ -4
Step-by-step explanation:
In general, swap x and y, then solve for y. Quadratics, as in the first problem, do not have an inverse function: the inverse relation is double-valued, unless the domain is restricted. Here, we're just going to consider these to be "solve for ..." problems, without too much concern for domain or range.
__
1) x = f(y)
x = (1/4)(y -6)² +1
4(x -1) = (y-6)² . . . . . . subtract 1, multiply by 4
±2√(x -1) = y -6 . . . . square root
y = 6 ± 2√(x -1) . . . . inverse relation
f⁻¹(x) = 6 ± 2√(x -1) . . . . in functional form
__
3) x = √(y +2) -4
x +4 = √(y +2) . . . . add 4
(x +4)² = y +2 . . . . square both sides
y = (x +4)² -2 . . . . . subtract 2
__
5) x = ∛(y +4) +4
x -4 = ∛(y +4) . . . . . subtract 4
(x -4)³ = y +4 . . . . . cube both sides
y = (x -4)³ -4 . . . . . . subtract 4