Answer:
The simple interest rate is 5%.
This is possible with a rate of 6%, since in this case, his amount earned will be $5,208.
Step-by-step explanation:
This is a simple interest problem.
The simple interest formula is given by:
[tex]E = P*I*t[/tex]
In which E is the amount of interest earned, P is the principal(the initial amount of money), I is the interest rate(yearly, as a decimal) and t is the time.
After t years, the total amount of money is:
[tex]T = E + P[/tex]
Joshua has $4,200 to invest for college. If Joshua invests $4,200 for 3 years and earns $630, what is the simple interest rate?
We have that [tex]P = 4200, E = 630, t = 3[/tex]. We have to find I.
[tex]E = P*I*t[/tex]
[tex]630 = 4200*I*3[/tex]
[tex]I = \frac{630}{4200*3}[/tex]
[tex]I = 0.05[/tex]
The simple interest rate is 5%.
Joshua’s goal is to have $5,000 after 4 years. Is this possible if he invests with a rate of return of 6%?
We have to find T when [tex]P = 4200, t = 4, I = 0.06[/tex]
So
[tex]E = P*I*t[/tex]
[tex]E = 4200*0.06*4[/tex]
[tex]E = 1008[/tex]
[tex]T = E + P = 4200 + 1008 = 5208[/tex]
This is possible with a rate of 6%, since in this case, his amount earned will be $5,208.
A company that manufactures video cameras produces a basic model and a deluxe model. Over the past year, 41% of the cameras sold have been of the basic model. Of those buying the basic model, 31% purchase an extended warranty, whereas 48% of all deluxe purchasers do so. If you learn that a randomly selected purchaser has an extended warranty, how likely is it that he or she has a basic model
Answer:
[tex]75.6\%[/tex]
Step-by-step explanation:
Let B be the event of buying a basic model.
Given that P(B) = 41%
Let D be the event of buying a basic model.
Given that P(D) = 1 - 41% = 59%
Let E be the event of extended warranty.
Given that:
P(E [tex]\cap[/tex] B) = 31% and
P(E [tex]\cap[/tex] D) = 48%
P(E) = P(E [tex]\cap[/tex] B) [tex]\times[/tex] P(B) + P(E [tex]\cap[/tex] D) [tex]\times[/tex] P(D)
P(E) = 31% [tex]\times[/tex] 41% + 48% [tex]\times[/tex] 59% = 0.4103
To find: P(B/E)
Formula:
[tex]P(B/E) = \dfrac{P(E \cap B)}{P(E)}[/tex]
[tex]\Rightarrow \dfrac{0.31}{0.41}\\\Rightarrow 0.756\\\Rightarrow 75.6\%[/tex]
So, the correct answer is [tex]75.6\%[/tex].
Translate to a system of equations: Twice a number plus three times a second number is negative one. The first number plus four times the second number is two.
Answer:
work is shown and pictured
Assume that 1100 births are randomly selected and exactly 556 of the births are girls. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that the result is far from what is typically expected.
Answer:
The sample proportion for the births that are girls is 0.505. It is slightly higher than the expected value of 0.5, but the right way to answer if it is an unusual proportion is by performing an hypothesis test.
The hypothesis test results in not enough evidence to claim that the outcome is unlikely. This sample result has a probability of 0.7627 of appearing by pure chance in a population with proportion p=0.5.
Step-by-step explanation:
This is a hypothesis test for a proportion.
The claim is that the proportion of girls birth differs significantly from the expected proportion (50%).
Then, the null and alternative hypothesis are:
[tex]H_0: \pi=0.5\\\\H_a:\pi\neq 0.5[/tex]
The significance level is 0.05.
The sample has a size n=1100.
The sample proportion is p=0.505.
p=X/n=556/1100=0.505
The standard error of the proportion is:
[tex]\sigma_p=\sqrt{\dfrac{\pi(1-\pi)}{n}}=\sqrt{\dfrac{0.5*0.5}{1100}}\\\\\\ \sigma_p=\sqrt{0.000227}=0.015[/tex]
Then, we can calculate the z-statistic as:
[tex]z=\dfrac{p-\pi-0.5/n}{\sigma_p}=\dfrac{0.505-0.5-0.5/1100}{0.015}=\dfrac{0.005}{0.015}=0.302[/tex]
This test is a two-tailed test, so the P-value for this test is calculated as:
[tex]\text{P-value}=2\cdot P(z>0.302)=0.7627[/tex]
As the P-value (0.7627) is greater than the significance level (0.05), the effect is not significant.
The null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the proportion of girls birth differs significantly from the expected proportion (50%).
A trash company is designing an open-top, rectangular container that will have a volume of 1715 ft cubed. The cost of making the bottom of the container is $5 per square foot, and the cost of the sides is $4 per square foot. Find the dimensions of the container that will minimize total cost.
Answer:
14 ft × 14 ft × 8.75 ft
Step-by-step explanation:
A garbage company is designing an open rectangular container that should have a volume of 1,715 cubic feet.
So we have the length of the container = "x" ft, the width of the container = "y" ft and the height of the container = "z" ft
Therefore the volume of the rectangular container would be:
x * y * z = 1715 ft³
z = 1715 / x * y
The cost of making the bottom of the container is $ 5 per square foot, that is:
5 * (x * y)
Now, area of all sides of the container would be:
2 * (x * z + y * z) = 2 * z * (x + y)
We know that it has been given that the cost of making all the sides of the container is = $ 4 per square foot, so:
4 * (2 * z * (x + y)) = 8 * z * (x + y)
In total the costs would be:
5 * (x * y) + 8 * z * (x + y)
If we replace z, in the previous equation we have:
5 * (x * y) + 8 * (1715 / x * y) * (x + y)
solving, and we would have that the total cost would be:
C = 5 * (x * y) + 13720 / x + 13720 / y
Now we will find the derivative of C and make it equal to zero:
dC / dx = 0; dC / dy = 0
For dC / dx = 0:
dC / dx = 5 * y + 13720 * -1 / (y ^ 2) + 13720 * 0
0 = 5 * y - 13720 / y ^ 2
5 * y = 13720 / y ^ 2
y ^ 3 = 13720/5 = 2744
y = 14
For dC / dy = 0:
dC / dy = 5 * x + 13720 * 0 + 13720 * -1 / (x ^ 2)
0 = 5 * x - 13720 / x ^ 2
5 * x = 13720 / x ^ 2
x ^ 3 = 13720/5 = 2744
x = 14
now for z:
z = 1715 / (14 * 14)
z = 8.75
Therefore, the dimensions of the container should be 14 ft × 14 ft × 8.75 ft to minimize manufacturing cost.
Please help. I’ll mark you as brainliest if correct!
Answer:
(0. 4)
(-2, 0)
Step-by-step explanation:
The y- coordinates (output) at the highest and lowest points are called the absolute maximum and absolute minimum, respectively.As per given graph,
absolute maximum is 4, point (0, 4)absolute minimum is 0, point (-2, 0)Solve for x: 3x - 5 = 2x + 6.
Your answer
Answer:
3x-5=2x+6
x-5=6
x=11
Please help. I’ll mark you as brainliest if correct!!!!
Answer:
a= 2/5
b= -3/5
Step-by-step explanation:
We need to multiply the numerator and denominator by -i (conjugate) to cancel out i in the denominator
[tex]\frac{(3+2i)(-i)}{5i(-i)}[/tex]
This simplifies to:
[tex]\frac{-3i+-2i^{2} }{-5i^{2} }[/tex]
This further simplifies to:
[tex]\frac{-3i +2}{5}[/tex]
Can be rewritten as:
[tex]\frac{2}{5} +-\frac{3}{5} i[/tex]
a = 2/5
b = -3/5
On the map, Seattle, Portland, and Boise form a triangle whose sides are shown in the figure below. If the actual distance from Seattle to Boise is 400 miles, find the distance from Seattle to Portland.
Answer:
150 miles
Step-by-step explanation:
If the distance between Seattle and Boise is 400 miles and the image illustrates 4", then there must be a proportionate between the two values. Therefore, if the distance between Seattle and Portland is 1.5", then the real distance must be 150 miles.
The given line segment passes through the points (0, -3) and (-5, -4).
What is the equation of the line that is parallel to the given line and passes through the point (-2, 2)?
Answer:
y= 1/5x + 12/5
Step-by-step explanation:
Points: (0, -3) and (-5, -4)Line: y= mx+bSlope: m=(y2-y1)/(x2-x1)= (-4+3)/(-5-0)= -1/-5= 1/5Y-intercept: -3= 0*1/5+b ⇒ b= -3So the line is: y= 1/5x - 3Parallel line to this has same slope and passes through the point (-2, 2)
Its y- intercept is: 2= 1/5(-2)+b ⇒ b= 2+2/5= 12/5The required equation in slope- intercept form is:
y= 1/5x + 12/5Here is rectangle A. Block A. Rectangle B is ¹/₅ longer than A Block B. Rectangle C is ¹/₃ longer than B Block C. The total length of all three rectangles is 133 cm. How much longer is rectangle C than B?
Answer:
Rectangle C is 14 cm longer than B
Step-by-step explanation:
Let x be the length of Rectangle A. Rectangle B is ¹/₅ longer than A Block B,
Therefore the length of rectangle B is:
[tex]x+\frac{1}{5}x[/tex]
Rectangle C is ¹/₃ longer than B, therefore the length of rectangle c is:
[tex]x+\frac{1}{5}x+\frac{1}{3}(x+\frac{1}{5}x) =x+ \frac{1}{5}x+\frac{1}{3}x+\frac{1}{15}x=x+\frac{9}{15}x[/tex]
The total length of all three rectangles is 133 cm.
Length of rectangle A + Length of rectangle B + Length of rectangle C = 133 cm
[tex]x+x+\frac{1}{5}x +x+\frac{9}{15}x=133\\x+x+x+\frac{1}{5}x +\frac{9}{15}x=133\\3x+\frac{12}{15}x=133\\ 45x+12x=1995\\57x=1995\\x=35cm[/tex]
Therefore the length of rectangle A is 35 cm, the length of rectangle B is [tex]35+\frac{1}{5}*35=42\ cm[/tex] and the length of rectangle C is [tex]35+\frac{9}{15}*35=56\ cm[/tex]
Rectangle C is ¹/₃ longer than B, which is 14 cm (42\3) longer than B
A diagonal of a cube measures 30 inches. The diagonal of a face measures StartRoot 600 EndRoot inches.
In inches, what is the length of an edge of the cube? Round the answer to the nearest tenth.
Answer:
17.3 Inches
Step-by-step explanation:
Given that the diagonal of a cube = 30 inches
For a cube of side length s, Length of its diagonal [tex]=s\sqrt{3}[/tex]
Therefore:
[tex]s\sqrt{3}=30\\$Divide both sides by \sqrt{3}\\s=30 \div \sqrt{3}\\s=17.3$ inches (to the nearest tenth.)[/tex]
Side Length of the cube is 17.3 Inches.
Answer:
17.3
Step-by-step explanation:
Edge 2020
The results of a linear regression are shown below.
y= ax + b
a = -1.15785
b= 139.3171772
r= -0.896557832
r2 = 0.8038159461
Which phrase best describes the relationship between x and y?
1)Strong Postive Correlation
2)Strong Negative Correlation
3)Weak Positive Correlation
4)Weak Negative Correlation
Answer:
2) Strong Negative Correlation
Step-by-step explanation:
With the value of r we have both the information about the sign of the relationship and the strength of this relationship.
As the value of r is negative, we can conclude that the correlation between x and y is negative.
Also, as the absolute value of r is close to 1, we can conclude that this relationship is strong.
The strength can also be seen in the value of r2, which is also close to 1, but this value does not give information about the sign.
The value of the slope a, being negative, can also tell us that the relation between x and y is a negative correlation.
What’s the correct answer for this?
Answer:
D
Step-by-step explanation:
Length × Width = Area
So we'll substitute the Area of the circle having formula, πr²
Company A makes a large shipment to Company B. Company B can reject the shipment if they can conclude that the proportion of defective items in the shipment is larger than 0.1. In a sample of 400 items from the shipment, Company B finds that 59 are defective. Conduct the appropriate hypothesis test for Company B using a 0.05 level of significance.
Answer:
[tex]z=\frac{0.1475-0.1}{\sqrt{\frac{0.1(1-0.1)}{400}}}=3.17[/tex]
The p value for this case would be given by:
[tex]p_v =P(z>3.17)=0.00076[/tex]
For this case the p value is lower than the significance level so then we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 0.1 and then Company B can reject the shipment
Step-by-step explanation:
Information provided
n=400 represent the random sample taken
X=59 represent number of defectives from the company B
[tex]\hat p=\frac{59}{400}=0.1475[/tex] estimated proportion of defectives from the company B
[tex]p_o=0.1[/tex] is the value to verify
[tex]\alpha=0.05[/tex] represent the significance level
z would represent the statistic
[tex]p_v[/tex] represent the p value
Hypothesis to test
We want to verify if the true proportion of defectives is higher than 0.1 then the system of hypothesis are.:
Null hypothesis:[tex]p \leq 0.1[/tex]
Alternative hypothesis:[tex]p > 0.1[/tex]
The statistic would be given by:
[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)
Replacing the info given we got:
[tex]z=\frac{0.1475-0.1}{\sqrt{\frac{0.1(1-0.1)}{400}}}=3.17[/tex]
The p value for this case would be given by:
[tex]p_v =P(z>3.17)=0.00076[/tex]
For this case the p value is lower than the significance level so then we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 0.1 and then Company B can reject the shipment
3. Write 52/6
as a mixed number.
Give your answer in its simplest form.
Answer:
26/3 as an improper fraction in simplest form. :)
Step-by-step explanation:
8. Peter and his partner are conducting a physics experiment on pendulum motion. Their 30-cm
pendulur traverses an arc of 15 cm. To the nearest degree, how many degrees of rotation did
the pendulum swing?
Answer: 90/pi degrees
Step-by-step explanation:
It forms a 15cm arc from a circle of radius 30 cm.
The diameter is 30*2*pi = 60pi cm. So the arc is 15/60pi = 1/4pi of the way around a 360 degree circle. This is 1/4pi * 360 = 90/pi degrees.
Hope that helped,
-sirswagger21
The pendulum will swing 28.68° if the 30-cm pendulum traverses an arc of 15 cm.
What is a circle?It is defined as the combination of points that, and every point has an equal distance from a fixed point (called the center of a circle).
We know that relationship between arc length s and central angle θ:
s = rθ
Where r is the radius of the circle
We have s = 15 cm
r = 30 cm
15 = (30)(θ)
θ = 0.5 radians
To convert it to a degree, multiply it by 180/π
θ = 0.5(180/π)
θ = 28.647 ≈ 28.68°
Thus, the pendulum will swing 28.68° if the 30-cm pendulum traverses an arc of 15 cm.
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determine whether the forces in the pair are pulling at right angles to each other for the values. a-3.4 and b=2.6, which are legs of a right triangle, find c, the hypotenuse, to the nearest tenth
Answer:
4.3 units
Step-by-step explanation:
In this question we use the Pythagorean Theorem which is shown below:
Data are given in the question
Right angle
a = 3.4
b = 2.6
These two are legs of the right triangle
Based on the above information
As we know that
Pythagorean Theorem is
[tex]a^2 + b^2 = c^2[/tex]
So,
[tex]= (3.4)^2 + (2.6)^2[/tex]
= 11.56 + 6.76
= 18.32
That means
[tex]c^2 = 18.56[/tex]
So, the c = 4.3 units
Tricia has a birthday party. During the party, she opened 36 gifts, which was 60% of all her gifts. After the party, she opened the rest of the gifts and found that 25% of them were the same present, so she returned all but one of the duplicate gifts. How many gifts did she return?
Answer:
She returned 5 gifts.
Step-by-step explanation:
36 gifts is 60% = 0.6 of all the gifts that she received. How many presents are 100% = 1?
36 gifts - 0.6
x gifts - 1
0.6x = 36
x = 36/0.6
x = 60
She received 60 gifts.
She opened the rest of the gifts and found that 25% of them were the same present
The rest is 60 - 36 = 24 gifts.
25% is (1/4)*24 = 6 duplicate figts
She returned all but one of the duplicate gifts.
That is, she returned 6 - 1 = 5 gifts.
A horizontal line contains points A, C, B. 2 lines extend from point C. A line extends to point E and another line extends to point D. An arc represents angle A C D.
Ray CE is the angle bisector of AngleACD. Which statement about the figure must be true?
mAngleECD = One-halfmAngleECB
mAngleACE = one-halfmAngleACD
AngleACE Is-congruent-to AngleDCB
AngleECDIs-congruent-to AngleACD
Answer:
Option (2).
Step-by-step explanation:
In the figure attached,
A, C and B are the points lying on a straight line.
2 lines EC and DC have been drawn by extending the lines from C to E and D respectively.
Ray CE is the angle bisector of ∠ACD.
That means CE divides ∠ACD in two equal parts.
m∠ACE = m∠DCE
Since m∠ACD = m∠ACE + m∠DCE
= 2(m∠ACE)
m∠ACE = [tex]\frac{1}{2}(\angle ACD)[/tex]
Therefore, option (2) will be the answer.
Answer:
b
Step-by-step explanation:
took test
Need help ASAP please!!
Answer:
AOB = 73
BOC = 107
Step-by-step explanation:
So make an equation.
9x + 27 = 180
9x = 153
x = 17
AOB = 73
BOC = 107
If (x + k) is a factor of f(x), which of the following must be true?
f(K) = 0
fl-k)=0
A root of f(x) is x = k.
A y intercept of f(x) is x = -k.
Answer:
f(-k)=0Step-by-step explanation:
(x + k) is a factor of f(x)
x+k=0 => x= -k; -k is a root of f(x)
=> f(-k)=0
[tex](x + k) is a factor of f(x)x+k=0 = > x= -k; -k is a root of f(x)= > f(-k)=0[/tex]
So the correct option is B.fl-k)=0.
What is a root function example?
The cube root function is f(x)=3√x f ( x ) = x 3 . A radical function is a function that is defined by a radical expression. The following are examples of rational functions: f(x)=√2x4−5 f ( x ) = 2 x 4 − 5 ; g(x)=3√4x−7 g ( x ) = 4 x − 7 3 ; h(x)=7√−8x2+4 h ( x ) = − 8 x 2 + 4 7 .
What is the root function?
The root function is used to find a single solution to a single function with a single unknown. In later sections, we will discuss finding all the solutions to a polynomial function. We will also discuss solving multiple equations with multiple unknowns. For now, we will focus on using the root function.
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Liam needs a guitar case. It must be 1.18 m long. Select the case that is suitable? 11.8mm,118cm,1.8m ,11.18mm
Answer:
118 cm
Step-by-step explanation:
1 m = 100 cm
1 m = 1000 mm
1.18 m = 118 cm = 1180 mm
11.8 mm ----> too small
118 cm ----> just right
1.8 m ----> too big
11.18 mm ----> too small
Where the above dimensions are given, the suitable guitar case for Liam would be the one that is 1.8 m long.
How is this so?Since Liam's guitar case needs to be 1.18 m long, we need to select the option that is closest in length without exceeding it.
Among the given options, 11.8 mm and 11.18 mm are too small, and 118 cm is equal to 1.18 m, which exceeds the required length.
Hence , the only suitable option is 1.8 m, which matches Liam's requirement of a guitar case with a length of 1.18 m.
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The manager of the motor pool wants to know if it costs more to maintain cars that are driven more often. Data are gathered on each car in the motor pool regarding number of miles driven (X) in a given year and maintenance costs for that year (Y) in thousands of dollars. The regression equation is computed as: Y-60+0.08X, and the p-value for the slope estimate is 0.7. What conclusion can we draw from this study? a. Cars that are driven more tend to cost more to maintain. b. There's no statistically significant linear relationship between the number of miles driven and the maintenance cost c. The correlation between the response variable and independent variable is significant. d. The slope estimate is significantly different from zero.
Answer:
b. There's no statistically significant linear relationship between the number of miles driven and the maintenance cost
Step-by-step explanation:
The p-value for the slope estimate show us how strong is the certainty that there are a linear relationship between both variables. In this case, the p-value for the slopes shows if there is a significant relationship between the number of miles driven and the maintenance cost.
If we have a high p-value like 0.7 we can said that there is no certainty in the linear relationship. it means that there's no statistically significant linear relationship between the number of miles driven and the maintenance cost.
Cheeseburgers to go has advertised for counter help. If you take the job, you will be working 18 hours
a week for $69.20 per week. How much would you make an hour?
Answer:
about $3.84
Step-by-step explanation:
you do 69.20 divided by 18
One-third times the difference of a number and 5 is
Which equation best shows this?
3
One possible first step in solving the equation in the above problem is to
The value of the number is
Answer:
the value of x is 3
Step-by-step explanation:
Hope this helps!!!! :)
Answer:
one is a
two is c
three is b
Step-by-step explanation:
The most common form of color blindness is an inability to distinguish red from green. However, this particular form of color blindness is much more common in men than in women (this is because the genes corresponding to the red and green receptors are located on the X-chromosome). Approximately 79% of American men and 0.4% of American women are red-green color-blind.1 Let CBM and CBW denote the events that a man or a woman is color-blind, respectively.
(a) If an Americal male is selected at random, what is the probability that he is red-green color-blind? P(CBM) =
(b) If an American female is selected at random, what is the probability that she is NOT red-green color-blind? P (not CBW) =
(c) If one man and one woman are selected at random, what is the probability that neither are red-green color-blind? P=(neither is color-blind) =
(d) If one man and one woman are selected at random, what is the probability that at least one of them is red-green color-blind? P=(at least one is color-blind)
Answer:
(a) P(CBM) = 0.07
(b) P(not CBW) = 0.996
(c ) P(neither is color-blind) = 0.926
(d) P=(at least one is color-blind) = 0.074
Step-by-step explanation:
The correct data is that Approximately 7% of American men and 0.4% of American women are red-green color-blind.
(a) Probability that he is red-green color-blind:
[tex]P(CBM) = 0.07[/tex]
(b) Probability that she is NOT red-green color-blind:
[tex]P(not\ CBW) =1- P(CBW)\\P(not\ CBW) = 1 -0.004\\P(not\ CBW) =0.996[/tex]
(c) Probability that neither are red-green color-blind
[tex]P(neither) = P(not\ CBW)*P(not\ CBM) \\P(neither) = 0.996 *(1-0.07)\\P(neither)=0.926[/tex]
(d) Probability that at least one of them is red-green color-blind
[tex]P(at\ least\ one) = 1- P(neither) \\P(at\ least\ one) = 1-0.926\\P(at\ least\ one) = 0.074[/tex]
On a piece of paper, graph fx) = 2• (0.5)*. Then determine which answer choice matches the graph you drew.
Answer:
Graph A
Step-by-step explanation:
The common ratio is less than 1, so the graph will be decreasing. The initial value is 2, so the y-intercept will be 2. Graph A fits this criteria.
I hope this helps :))
The graph A is correct.
What is a graph?A diagram (such as a series of one or more points, lines, line segments, curves, or areas) that represents the variation of a variable in comparison with that of one or more other variables.
The equation is,
[tex]y=2(0.5)^{x}[/tex]
Plotting the graph, we get,
Option A
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Identify the lower class limits, upper class limits, class width, class midpoints, and class boundaries for the given frequency distribution. Also identify the number of individuals included in the summary.
Age (yr) when award was won:
20-24
25-29
30-34
35-39
40-44
45-49
50-54
Frequency:
29
36
15
3
6
2
2
Answer:
Lower class Limit: 20,25,30,35,40,45,50
Upper class limit: 24,29,34,39,44,49,54
Class width: 4
Class Midpoints : 22,27,32,37,42,47,52
Class Boundries : 19.5,24.5,29.5,34,5,39.5,44.5,49.5,54.5
Total Individuals: 93
Step-by-step explanation:
Lower class limit is the lowest value of a class e.g in the first class, the lowest value is 20. Similarly find lower class limit of othere classes.
Upper class limit is the highest value of a class e.g in the first class, the highest value is 24. Similarly find upper class limit of othere classes.
Class width is the difference between highest and lowest value of a class e.g 24-20=4
Class Midpoints can be found by adding lowest and highest value of a class and dividing it by 2 e.g (20+24)/2 = 22
Class boundaries are the halfway point which seperates the classes e.g for first classes, clasee boundry is (19.5,24.5)
Total individuals are founf by adding all the frequencies.
I need help with this one
Answer:
2 2/3
Step-by-step explanation:
A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. The mean is found to be 7.8 reproductions and the population standard deviation is known to be 2.2. If a sample of 697 was used for the study, construct the 85% confidence interval for the true mean number of reproductions per hour for the bacteria. Round your answers to one decimal place.
Answer:
The 85% confidence interval is ( 7.7 , 8.0 )
Step-by-step explanation:
In order to find the 85% confidence interval you use the following formula:
[tex]\overline{x}\pm Z_{\alpha/2}\frac{\sigma}{\sqrt{n}}[/tex] (1)
where
[tex]\overline{x}[/tex]: mean of number of bacteria reproduces per hour = 7.8
σ: standard deviation = 2.2
n: sample size = 967
α: 1 - 0.85 = 0.15
Zα/2: Z factor of the density distribution = 1.44
You replace the values of all parameters in the equation (1):
[tex]7.8\pm (1.44)\frac{2.2}{\sqrt{697}}\\\\7.8\pm0.119\\\\[/tex]
Then, the confidence interval is:
[tex](7.8-0.119,7.8+0.119)\\\\(7.7,8.0)[/tex]