The first differences are 8, 14, 20.
The second differences are 6.
Half of 6 is 3, so the first term of the sequence is 3n^2.
If you subtract 3n^2 from the sequence you get 0,-1,-2,-3 which has the nth term of -n + 1.
Therefore your final answer will be 3n^2 - n + 1
If the center of a circle is at
(5,-3) and its radius is 4, complete
its equation:
Answer:
Step-by-step explanation:
[tex](x-5)^2+(y-(-3))^2=16[/tex]
Please answer I need help!
Answer:
c & d
Step-by-step explanation:
the description matches the information in the table
Answer: A, B, C
Step-by-step explanation:
domain = x
range = y
Choose the equation of the graph shown below:
y = |x - 1| - 3
y = |x + 1| - 3
y = |x - 1| + 3
Answer:
y=[x+1]-3 because it's at the end of the line
Meru Peak is 765 m higher than Mt. Kilimanjaro. If the sum of their heights is 12,555 m, find the height of Mt. Kilimanjaro.
Answer:
Step-by-step explanation:
Let P=Mount Peak
Let K=Mount Killimanjaro
The equation should then be
12555=P+K ...1
P=K+765 ... 2
sub equation 2 into 1
12555=P+P+765
12555=2P+765
12555-765=2P+765-765 (subtracting 765 from both sides)
11790=2P
P=5895, now that we know P
we just make a new equation that was similiar to 1
12555=5895+K
K=6660
the height of Mount K is 6660 Metres
5. Lana pays a semiannual premium of $300 for automobile insurance, a monthly premium of $100 for health insurance, and an annual premium of $700 for life insurance.
Find her monthly expense.
Hey there! I'm happy to help!
We want to find out how much Lana pays per month. Let's dissect each payment we are given so we can find our monthly expense.
---------------------------------------------------------------------------
AUTOMOBILE INSURANCE
$300 for automobile insurance semiannually
The prefix semi- means half. Annual means year. So, she is paying $300 every half year, or six months. So, we can divide 300 by 6 to find how much she pays in one month!
300/6=50
Therefore, she pays $50 a month for automobile insurance.
---------------------------------------------------------------------------
HEALTH INSURANCE
We are told here that she pays $100 every month for health insurance. We don't need do anything else here!
---------------------------------------------------------------------------
LIFE INSURANCE
We see that Lana pays $700 per year on life insurance. We can divide this by 12 to find out how much there is in 1 month!
700/12≈58.33
Therefore, she pays $58.33 every month on life insurance.
---------------------------------------------------------------------------
SOLUTION
Now, we just add all of these monthly totals up to find Lana's monthly expense.
50+100+58.33=208.33
Therefore, Lana's monthly expense is $208.33.
I hope that this helps! Have a wonderful day!
Arsha predicted that she would sell 225 magnets. She actually sold 240 magnets. What are the values of a and b in the table below? Percent Error Item Approximate value Exact value Error Absolute error Ratio Percent error Magnets 225 240 a b a = Negative StartFraction 15 over 225 EndFraction; b = negative 6.7 percent a = Negative StartFraction 15 over 240 EndFraction; b = negative 6.25 percent a = StartFraction 15 over 240 EndFraction; b = 6.25 percent a = StartFraction 15 over 225 EndFraction; b = 6.7 percent
Answer:
c
Step-by-step explanation:
2009-2202+1234-2 equals
Step-by-step explanation:
1039
This is the correct answer
help asap giving branlist!!!
Answer:
option 2
Step-by-step explanation:
Because (0, 900) is a point on the line it means that it costs $900 to make the commercial. A slope of 110 means that they pay $110 every time it's aired so the answer is Option 2.
A tree was 9 feet tall. One year later, the tree was 16 feet tall. Write an equation and use mental math to find how many feet f the tree grew.
Answer:
7 ftStep-by-step explanation:
let the height height of the tree be "h"
Hence the tree's height h=9 ft
one year later,let the height of the tree increased by x ft
hence
[tex]9 + x = 16[/tex] --------This is the equation for the growth of the tree
In order to solve for the added height(growth) of the tree we need to solve for x
[tex]9 + x = 16\\x=16-9\\x=7ft[/tex]
Use the equation and type the ordered-pairs. y = log 2 x {(1/2, a0), (1, a1), (2, a2), (4, a3), (8, a4), (16, a5)}
Answer:
the answer is 1/2,a0
Step-by-step explanation:
If 4000 hours= 240,000 minutes and you make a 10 minute video, how many people will need to view the video to get 4000 hours of view time?
Answer:
24000
Step-by-step explanation:
because 24000 * 10 =240000
at the last minute deal Don and Mary booked a 7 day cruise for a total of $670. If the normal price for a couple is $1340, what discount percent did Don ans Mary recieve?
Answer:50%
Step-by-step explanation:670/1340 = 1/2 = 50%
In the circle below, CD is a diameter. If AE=10, CE=4, and AB=16, what is
the length of the radius of the circle?
Please Help ASAP
Answer:
(D)9.5 Units
Step-by-step explanation:
We have two chords CD and AB intersecting at E.
Using the theorem of intersecting chords
AE X EB =CE X ED
AE=10CE=4AB=16AB=AE+EB
16=10+EB
EB=16-10=6
Therefore:
AE X EB =CE X ED
10 X 6 = 4 X ED
ED =60/4 =15
Therefore:
CD=CE+ED
=4+15
CD=19
Recall that CD is a diameter of the circle and;
Radius =Diameter/2
Therefore, radius of the circle =19/2 =9.5 Units
b. Find the probability that two or fewer heads are observed in three tosses. (Round your answer to three decimal places.) c. Find the probability that at least one head is observed in three tosses. (Round your answer to three decimal places.) d. Find the expected value of X. (Round your answer to one decimal place.) e. Find the standard deviation of X. (Round your answer to three decimal places.)
Answer:
(a) Probability distribution is prepared below.
(b) The probability that two or fewer heads are observed in three tosses is 0.875.
(c) The probability that at least one head is observed in three tosses is 0.875.
(d) The expected value of X is 1.5.
(e) The standard deviation of X is 2.121.
Step-by-step explanation:
The complete question is: A fair coin is tossed three times. Let X be the number of heads observed in three tosses of this fair coin.
(a) Find the probability distribution of X.
(b) Find the probability that two or fewer heads are observed in three tosses. (Round your answer to three decimal places.)
(c) Find the probability that at least one head is observed in three tosses. (Round your answer to three decimal places.)
(d) Find the expected value of X. (Round your answer to one decimal place.)
(e) Find the standard deviation of X. (Round your answer to three decimal places.)
Now, firstly the sample space obtained in three tosses of a fair coin is given as;
Sample Space (S) = {HHH, HHT, HTH, THH, HTT, TTH, THT, TTT}
(a) The Probability distribution of X is given below;
Number of Heads (X) P(X) [tex]X \times P(X)[/tex] [tex]X^{2} \times P(X)[/tex]
0 [tex]\frac{1}{8}[/tex] = 0.125 0 0
1 [tex]\frac{3}{8}[/tex] = 0.375 0.375 0.375
2 [tex]\frac{3}{8}[/tex] = 0.375 0.75 3
3 [tex]\frac{1}{8}[/tex] = 0.125 0.375 3.375
Total 1.5 6.75
(b) The probability that two or fewer heads are observed in three tosses is given by = P(X [tex]\leq[/tex] 2)
P(X [tex]\leq[/tex] 2) = P(X = 0) + P(X = 1) + P(X = 2)
= 0.125 + 0.375 + 0.375
= 0.875
(c) The probability that at least one head is observed in three tosses is given by = P(X [tex]\geq[/tex] 1)
P(X [tex]\geq[/tex] 1) = 1 - P(X = 0)
= 1 - 0.125
= 0.875
(d) The expected value of X = E(X) = [tex]\sum (X \times P(X))[/tex]
= 1.5
(e) The Variance of X = V(X) = [tex]E(X^{2} ) - ( E(X))^{2}[/tex]
= [tex]\sum (X^{2} \times P(X))- (\sum (X \times P(X)))^{2}[/tex]
= [tex]6.75 - 1.5^{2}[/tex] = 4.5
Now, Standard deviation of X = [tex]\sqrt{V(X)}[/tex]
= [tex]\sqrt{4.5}[/tex] = 2.121.
Records on a fleet of trucks reveal that the average life of a set of spark plugs is normally distributed with a mean of 22,100 miles. The fleet owner purchased 18 sets and found that the sample average life was 23,400 miles; the sample standard deviation was 1,412 miles.
a) To decide if the sample data support the company records that the spark plugs average 22,100 miles, state your decision in terms of the null hypothesis. Use a 0.05 level of significance.
b) What is the critical value for the test using a 0.05 level of significance?
c) What is the test statistic?
d) What is your decision?
Answer:
a) We want to conduct a hypothesis in order to see if the true mean is 22100 or not, the system of hypothesis would be:
Null hypothesis:[tex]\mu = 22100[/tex]
Alternative hypothesis:[tex]\mu \neq 22100[/tex]
b) We need to find the degrees of freedom given by:
[tex] df =n-1 = 18-1=17[/tex]
And the critical values for this case are:
[tex] t_{\alpha/2}= 2.110[/tex]
c) [tex]t=\frac{23400-22100}{\frac{1412}{\sqrt{18}}}=3.906[/tex]
d) Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly different from 221100 mi
Step-by-step explanation:
Information provided
[tex]\bar X=23400[/tex] represent the sample mean
[tex]s=1412[/tex] represent the sample standard deviation
[tex]n=18[/tex] sample size
[tex]\mu_o =22100[/tex] represent the value to verify
[tex]\alpha=0.05[/tex] represent the significance level
t would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value
Part a
We want to conduct a hypothesis in order to see if the true mean is 22100 or not, the system of hypothesis would be:
Null hypothesis:[tex]\mu = 22100[/tex]
Alternative hypothesis:[tex]\mu \neq 22100[/tex]
Part b
We need to find the degrees of freedom given by:
[tex] df =n-1 = 18-1=17[/tex]
And the critical values for this case are:
[tex] t_{\alpha/2}= 2.110[/tex]
Part c
The statistic is given by:
[tex]t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}[/tex] (1)
Replacing the info we got:
[tex]t=\frac{23400-22100}{\frac{1412}{\sqrt{18}}}=3.906[/tex]
Part d
Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly different from 221100 mi
in the formula C=5/9(F-32),If C=35, then F=?
Step-by-step explanation:
Hope this helps
Hope this is correct
Answer:
F = 95°
Step-by-step explanation:
[tex]C=\frac{5}{9}(F-32)[/tex] is the formula to convert Fahrenheit to Celsius
If we have C = 35, we just need to plug in this number to its corresponding variable and then solve for F
[tex]35=\frac{5}{9}(F-32)[/tex] then we need to multiply both sides of the equation by 9 to get rid of the fraction on the right side[tex]35(9)=[\frac{5}{9}(F-32)](9)[/tex] then simplifies to [tex]315=(5)(F-32)[/tex] Now we can distribute the 5 on the right side to the (F - 32) to get 315 = 5F - 160Adding 160 to both sides we get 475 = 5FDividing both sides by 5 we get 95 = FThe company produces two types of goods in quantities of x and y, with market prices of €40 and 80€, respectively. If the production cost is given by function C(x,y) =2x^2+5y^2+120 and is not exceeding €250. What is the max profit obtained?
Answer:
€ 270
Step-by-step explanation:
Since the production cost C(x,y) = 2x² + 5y² + 120 is less than or equal to 250, we have 2x² + 5y² + 120 ≤ 250
The selling price S(x,y) = 40x + 80y
The profit P(x,y) = S(x,y) - C(x,y) = 40x + 80y - 2x² - 5y² - 120
Using the principle of lagrange multipliers, we want to maximize the profit P(x,y) under the condition that C(x.y) ≤ 250.
So, dP/dx = 40 - 4x , dC/dx = 4x, dP/dy = 80 - 10y , dC/dy = 10y
dP/dx + λdC/dx = 0
40 - 4x + 4λx = 0 (1)
4λx = 4x - 40
λ = (x - 10)/x
dP/dy + λdC/dy = 0
80 - 10y + 10λy = 0 (2)
substituting λ into (2), we have
80 - 10y + 10(x - 10)y/x = 0
multiplying through by x, we have
80x - 10xy + 10xy - 100y = 0
80x - 100y = 0
80x = 100y
x = 100y/80
x = 5y/4
substituting x into C(x,y) ≤ 250, we have
2(5y/4)² + 5y² + 120 ≤ 250
25y²/8 + 5y² + 120 ≤ 250
25y² + 40y² + 960 ≤ 2000
65y² ≤ 2000 - 960
65y² ≤ 1040
y² ≤ 1040/65
y² ≤ 16
y ≤ ±√16
y ≤ ± 4 since its quantity, we take the positive value.
So x = 5y/4 = 5(± 4)/4 = ± 5
So, x ≤ ± 5
For the maximum value for the profit, P(x,y), we take the maximum values of x and y which are x = 5 and y = 4. Substituting these values into P(x,y), we have
P(5,4) = 40(5) + 80(4) - 2(5)² - 5(4)² - 120
= 200 + 320 - 50 - 80 - 120
= 520 - 250
= 270
So, the maximum profit obtained is € 270
Which of the following are solutions to the quadratic equation? Check all that apply x^2 + 12x + 36 = 7
Answer:
x = -6 + [tex]\sqrt{7}[/tex], x = -6 - [tex]\sqrt{7}[/tex]
Step-by-step explanation:
(x + 6)² = 7
x + 6 = + or - [tex]\sqrt{7}[/tex]
x = -6 + [tex]\sqrt{7}[/tex], x = -6 - [tex]\sqrt{7}[/tex]
The solution of the quadratic equation is x = -6 +√7, x = -6 - √7.
What is a quadratic equation?A quadratic equation is a polynomial with a degree of 2 or the maximum power of the variable is 2 in quadratic equations. It has two solutions as its maximum power is 2.
Completing the square entails writing a quadratic in the form of a squared bracket and, if necessary, adding a constant. Finding the maximum or minimum value of the function and when it occurs is one application of completing the square.
Given that the quadratic equation is x² + 12x + 36 = 7.
(x + 6)² = 7
x + 6 = ±√7
x = -6 + √7 , x = -6 - √7
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Ronald needs a morning breakfast drink that will give him at least 390 calories. Orange juice has 130 calories in 8oz. How many ounces does he need to drink to reach his calorie goal?
Answer:
24 ounces of orange juice
Step-by-step explanation:
Given-
Calories needed=390 calories
Calories in 8oz juice=130 calorie
Therefore ounces of juice=(390/130)8
=3 x 8
=24 ounces
If Ronald needs a morning breakfast drink that will give him atleast 390 calories. Orange juice has 130 calories in 8oz. Then 24 ounces does he need to drink to reach his calorie goal.
What is Equation?Two or more expressions with an Equal sign is called as Equation.
Ronald needs a morning breakfast drink that will give him at least 390 calories.
Orange juice has 130 calories in 8oz.
We need to find how many ounces does he need to drink to reach his calorie goal
Calories needed=390 calories
Calories in 8oz juice=130 calorie
Three hundred ninety divided by one hundred thirty times of eight.
Therefore ounces of juice=(390/130)8
Three hundred ninety divided by one hundred thirty is three.
=3 x 8
Three times of eight is twenty four.
=24 ounces
Hence 24 ounces of orange juice does he need to drink to reach his calorie goal.
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Line segment ON is perpendicular to line segment ML
What is the length of chord ML?
0
20 units
24 units
26 units
30 units
13
P
8
M
N
Mark this and return
Answer:
The correct answer is B (24 units)
Step-by-step explanation:
One angle of a right triangle measures 51 degrees. What is the measure of the other small angle?
Answer:
39 degrees
Step-by-step explanation:
Given
triangle is right angled i.e one angle is 90 degrees
other angle is 51 degrees.
let the third angle be x degrees
we know that sum of angles of any triangle is 180 degrees
thus,
90 + 51+ x = 180
=> 141 + x = 180
=> x = 180 - 141 = 39.
Thus, measure of other small angle is 39 degrees.
Answer:
Step-by-step explanation:
m∠A+m∠B+m∠C = 180
90+51+x1= 180
41+x=180
x=39
A girl threw a marble 15 m vertically up in the air which later fell and settled at the bottom of a lake 7 m deep. Find the total distance travelled by the marble while falling down?
Answer:
22 m
Step-by-step explanation:
Total distance travelled by marble while falling down = height above surface of lake + depth of lake = 15 + 7 = 22 m
At a computer store, a customer is considering 7 different computers, 9 different monitors, 8 different printers and 2 different scanners. Assuming that each of the components is compatible with one another and that one of each is to be selected, determine the number of different computer systems possible.
Answer:
1008
Step-by-step explanation:
to find the number of combinations, just multiply everything. you will get 1008 :)
The distance between (2,0) and (5, -1) is
Answer:
(3, -1)
Step-by-step explanation:
5-2=3
0-1=-1 (keep 0, change - to a +, flip 1 to a -1)
For an exam given to a class, the students' scores ranged from 34 to 99 , with a mean of 78 . Which of the following is the most realistic value for the standard deviation: -14,3,0,56,15?
Clearly explain what's unrealistic about each of the other values.
Answer:
The most realistic value for the standard deviation is 15.
Step-by-step explanation:
The standard deviation of a distribution is a measure of dispersion. It is a measure of the spread of the distribution from the mean of the distribution. It expresses how far most of the distribution is from the mean.
Mathematically, the standard deviation is given as the square root of variance. And variance is an average of the squared deviations from the mean.
Mathematically,
Standard deviation = σ = √[Σ(x - xbar)²/N]
x = each variable (ranges from 34 to 99)
xbar = mean = 78
N = number of variables
Now taking the given possible values of the standard deviation one at a time,
-14
The standard deviation cannot be negative as it is a square root of the average of the sum of square deviations from the mean. Since the square of a number cannot be negative, it directly translates that the standard deviation cannot be negative.
3
A small standard deviation like 3 indicates that the distribution mostly centres about the mean, with very little variation. And the distribution given has a mean (78) that is very far away from at least one of the variables in the distribution. Hence, 3 is too low to pass ad the standard deviation of this distribution described.
0
A standard deviation of 0 indicates that all the variables in the distribution have the same value as the mean. That is, the distribution only contains 1 number, probably multiple times. So, this cannot be the standard deviation for the distribution described.
56
This value represents a value that is too high to express the spread of the distribution described. The mean (78) is very close to the maximum value of the distribution, and far away from the lower value(s), indicating that most of the distribution is in and around the upper values with a few variables closer to the lower limit. A standard deviation as high as 56 for a mean of 78 translates to a distribution with most of variables far from the mean, which isn't the case here.
Moreso, a simple add of the standard deviation to the mean or subtracting the standard deviation from the mean should give at least one of the results with values within the distribution.
(Mean) + (Standard deviation) = 78 + 56 = 134 >> 99 (outside distribution)
(Mean) + (Standard deviation) = 78 - 56 = 22 << 34 (also outside the distribution)
15
This is the most realistic value for the standard deviation as it represents what the distribution described above is.
The mean (78) being close to the maximum value of the distribution, and far away from the lower value(s) indicates that most of the distribution is in and around the upper values with a few variables closer to the lower limit.
So, 15 indicates a perfect blend of small deviations due to the high values close to the mean and the very high deviation from the evidently few lower values.
(Mean) + (Standard deviation) = 78 + 15 = 93 < 99 (within distribution)
(Mean) + (Standard deviation) = 78 - 15 = 63 > 34 (also within the distribution)
Hope this Helps!!!
When The most realistic value for the standard deviation is 15.
Step-by-step explanation:
Standard deviation The standard deviation of a distribution is a measure of dispersion. also, It is a measure of the spread of the distribution from the mean of the distribution. when It expresses how far most of the distribution is from the mean. Then according to Mathematically, the standard deviation is given as the square root of variance. And also variance is an average of the squared deviations from the mean.mathematically,When Standard deviation is = σ = √[Σ(x - xbar)²/N]After that x = each variable (ranges from 34 to 99)then xbar is = mean = 78Now N is = number of variablesThen we take the given possible values of the standard deviation one at a time, -14 after that The standard deviation cannot be negative as it is a square root of the average of the sum of square deviations from the mean. Since the square of a number cannot be negative, also it directly translates that the standard deviation cannot be negative. After that 3 no when A small standard deviation like 3 indicates that the distribution mostly centers about the mean, with very little variation. And also the distribution given has a mean (78) that is very far away from at least one of the variables in the distribution. Hence proof that is, 3 is too low to pass ad the standard deviation of this distribution described. Then 0 when A standard deviation of 0 indicates that all the variables in the distribution have the same value as the mean. That means is, the distribution only contains 1 number, probably multiple times. So that, this can't be the standard deviation for the distribution described. Now 56 This value represents a value that is too high to express the spread of the distribution described. when The mean (78) is very close to the maximum value of the distribution, and also far away from the lower value(s), indicating that most of the distribution is in and also around the upper values with a few variables closer to the lower limit. when A standard deviation as high as 56 for a mean of 78 translates to a distribution with most of the variables far from the mean, which isn't the case here. More so, when a simple addition of the standard deviation to the mean or subtracting the standard deviation from the mean should have given at least one of the results with values within the distribution.After that (Mean) + (Standard deviation) = 78 + 56 = 134 >> 99 (outside distribution)Then (Mean) + (Standard deviation) = 78 - 56 = 22 << 34 (also outside the distribution) Now last digit 15 This is the most realistic and also a value for the standard deviation as it represents what the distribution described above is.When The mean (78) is close to the maximum value of the distribution, and also far away from the lower value(s) indicates that most of the distribution is in and also that around the upper values with a few variables closer to the lower limit.So that, 15 indicates a perfect blend of small deviations due to the high values close to the mean and also the very high deviation from the evidently few lower values.Then (Mean) + (Standard deviation) = 78 + 15 = 93 < 99 (within distribution) After that (Mean) + (Standard deviation) =Thus, 78 - 15 = 63 > 34 (also within the distribution)
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In 1970, 59% of college freshmen thought that capital punishment should be abolished; by 2005, the percentage had dropped to 35%. Is the difference real, or can it be explained by chance
Answer:
there is significant distinction in opinion regarding abolition of capital punishment.
Step-by-step explanation:
Compute the p cost of 2-proportion for estimating difference. The Minitab output pronounces the p valu eto be 0.000. This is less than the assumed importance degree of alpha = 0.05. Therefore, reject null hypothesis to finish that there is significant distinction in opinion regarding abolition of capital punishment.
PLEASE HELP ALGEBRA PROBLEM!!! 20 POINTS ANSWER A-D
Answer:
A. 1.5 seconds
B. 36 feet
C. 0 feet
D. After 3 seconds
Step-by-step explanation:
I graphed it on desmos.
Find the percent of decrease from $2.00 to $1.25
Answer:
37.5
Step-by-step explanation:z
2.0-1.25=0.75
0.75/2.00 x 100
37.5% decrease
Find the radius of a circle given that the area is three times its circumference
Answer:
Radius of the circle = 6 units
Step-by-step explanation:
Let the radius of the circle be r
According to the given condition:
Area of the circle = 3 times the circumference of the circle
[tex]\therefore \pi r^2 =3\times 2\pi r\\\therefore r^2 = \frac{3\times 2\pi r}{\pi}\\\therefore r^2 = 3\times 2r\\\therefore r = 6\: units\\[/tex]
Construct the indicated confidence interval for the difference between the two population means. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal.
A paint manufacturer wished to compare the drying times of two different types of paint. Independent simple random samples of 11 cans of type A and 9 cans of type B were selected and applied to similar surfaces. The drying times, in hours, were recorded. The summary statistics are as follows.
Type A
x-bar1 = 75.7 hrs.
s1 = 4.5 hrs.
n1 = 11
Type B
x-bar2 = 64.3 hrs.
s2 = 5.1 hrs.
n2 = 9
Construct a 98% confidence interval for the difference for the mean drying time between paint A and paint B.
A. 6.08 hrs < μ1 - μ2 < 16.72 hrs
B. 5.85 hrs < μ1 - μ2 < 16.95 hrs
C. 5.78 hrs < μ1 - μ2 < 17.02 hrs
D. 5.92 hrs < μ1 - μ2 < 16.88 hrs
Answer:
Step-by-step explanation:
The formula for determining the confidence interval for the difference of two population means is expressed as
Confidence interval = (x1 - x2) ± z√(s²/n1 + s2²/n2)
Where
x1 = sample mean of type A paint
x2 = sample mean of type B paint
s1 = sample standard deviation type A paint
s2 = sample standard for type B paint
n1 = number of samples of type A paint
n2 = number of samples of type B paint
From the information given,
x1 = 75.7
s1 = 4.5
n1 = 11
x2 = 64.3
s2 = 5.1
n2 = 9
x1 - x2 = 75.7 - 64.3 = 11.4
√(s1²/n1 + s2²/n2) = √(4.5²/11 + 5.1²/9) = √4.709
Degree of freedom = (n1 - 1) + (n2 - 1)
df = (11 - 1) + (9 - 1) = 18
For the 98% confidence interval, the z score from the t distribution table is 2.552
Margin of error = 2.552√4.709 = 5.55
The upper boundary for the confidence interval is
11.4 + 5.55 = 16.95 hours
The lower boundary for the confidence interval is
11.4 - 5.55 = 5.85 hours
The correct option is
B. 5.85 hrs < μ1 - μ2 < 16.95 hrs
