Calculate the sample standard deviation and sample variance for the following frequency distribution of heart rates for a sample of American adults. If necessary, round to one more decimal place than the largest number of decimal places given in the data.

Lower Bound Upper Bound Frequency
56 64 11
65 73 15
74 82 14
83 91 4
92 100 11

Required:
a. What is the sample standard deviation?
b. What is the sample variance?

Answers

Answer 1

Answer:

[tex]\sigma = 12.5[/tex] ---- sample standard deviation

[tex]\sigma^2 = 157.2[/tex] ---- sample variance

Step-by-step explanation:

Solving (a): The sample variance

First, we calculate the midpoint of each class (this is the average of the limits)

So, we have:

[tex]x_1 = \frac{56 + 64}{2} = 60[/tex]

[tex]x_2 = \frac{65 + 73}{2} = 69[/tex]

And so on

So, the table becomes:

[tex]\begin{array}{cc}{x} & {f} & {60} & {11} & {69} & {15} & {78} & {14} & {87} & {4} & {96} & 11 \ \end{array}[/tex]

Calculate the mean

[tex]\bar x = \frac{\sum fx}{\sum f}[/tex]

[tex]\bar x = \frac{60*11+69*15+78*14+87*4+96*11}{11+15+14+4+11}[/tex]

[tex]\bar x = \frac{4191}{55}[/tex]

[tex]\bar x = 76.2[/tex]

The variance is:

[tex]\sigma^2 = \frac{\sum f(x - \bar x)^2}{\sum f - 1}[/tex]

So, we have:

[tex]\sigma^2 = \frac{(60 - 76.2)^2*11+(69 - 76.2)^2*15+(78 - 76.2)^2 *14+(87 - 76.2)^2*4+(96 - 76.2)^2*11}{11+15+14+4+11-1}[/tex]

[tex]\sigma^2 = \frac{8488.8}{54}[/tex]

[tex]\sigma^2 = 157.2[/tex]

The sample standard deviation is:

[tex]\sigma = \sqrt{\sigma^2[/tex]

[tex]\sigma = \sqrt{157.2[/tex]

[tex]\sigma = 12.5[/tex]

Solving (b): The sample variance

In (a), we calculate the sample variance to be:

[tex]\sigma^2 = 157.2[/tex]


Related Questions

One day, a café sells 3 more than twice the number of cappuccinos as they do lattes. They sold a total of 33 cappuccinos and lattes together.

Which equation could be used to find the number of lattes, x, sold at café

Answers

Answer:

x=6

Step-by-step explanation:

There are four white socks and six black socks in a drawer what is the probability of selecting a white sock not replacing it and then selecting another white sock

Answers

Answer:

Step-by-step explanation:

Add all the socks in the drawer to get a denominator

12

blue socks can be picked out of the

36

total socks, so

12

36

Then you take away one sock from the top and bottom, so you now have

11

35

Multiply the two numerators (

12

and

11

), then multiply the denominators (

36

and

35

), then divide the numerator by the denominator,

132

1260

, to get your answer.

Answer:

6/10

Step-by-step explanation:

1st step: 4+6=10

if y=8, evaluate the following expression: 40-5y​

Answers

0
Explanation:
y = 8

40 - 5 x 8
40 - 40
= 0

Have a nice day

Ali wants to attend more group exercise classes at his gym. This week, he plans to attend 1 cardio class and 5 weightlifting classes, which will last a total of 237 minutes. Next week, he hopes to attend 5 cardio classes and 5 weightlifting classes, which will last a total of 465 minutes.

a) Write a system of equations that represents the above situation.





b) Use the elimination method to show the length of the cardio class and the length of the weightlifting class.

Answers

Answer:

x + 5y = 237

5x + 5y = 465

Step-by-step explanation:

Let

x = length of cardio class

y = length of weightlifting class

x + 5y = 237 (1)

5x + 5y = 465 (2)

Using elimination method

Subtract (1) from (2) to eliminate y

5x - x = 465 - 237

4x = 228

x = 228/4

x = 57 minutes

Substitute x = 57 into (1)

x + 5y = 237 (1)

57 + 5y = 237

5y = 237 - 57

5y = 180

y = 180/5

y = 36 minutes

x = length of cardio class = 57 minutes

y = length of weightlifting class = 36 minutes

CAN YOU SOLVE THIS MATH PROBLEM 20 POINTS

Answers

The correct answer is A. x=22

Since the angles of a rectangle are right angles (90 degrees) you would set it up as 90=5x-20. Then combine like terms and solve the equation. (If you need me to show you how step by step tell me)
Answer is x=22 just did the work if interested for the work lemme know

using the digits 0-9 at most one time each fill in the boxes so that the fraction equals the decimal

Answers

Step-by-step explanation:

Z 00m

336"083"2553

(wZE2XQ) are

If you help me I’ll mark brainliest

Answers

Answer:

∠2=92°

Step-by-step explanation:

Using an angle formula, -8x+144=2x+74

Simplification:

-8x+144=2x+74

-8x+70=2x

70=10x

x=7

Therefore, each angle is 88°

Now, because ∠2 is adjacent to one of 88°, they add up to 180°

Therefore,

180°=88°+∠2

∠2=92°

According to the National Beer Wholesalers Association, U.S. consumers 21 years and older consumed 26.9 gallons of beer and cider per person during 2017. A distributor in Milwaukee believes that beer and cider consumption are higher in that city. A sample of consumers 21 years and older in Milwaukee will be taken, and the sample mean 2017 beer and cider consumption will be used to test the following null and alternative hypotheses:
H, :μ< 26.9
Ha : μ> 26.9
a. Assume the sample data led to rejection of the null hypothesis. What would be your conclusion about consumption of beer and cider in Milwaukee?b. What is the Type I error in this situation? What are the consequences of making this error?c. What is the Type II error in this situation? What are the consequences of making this error?

Answers

Answer:

Kindly check explanation

Step-by-step explanation:

If the null is rejected, then we conclude that the average Consumption of beer and cider by customers who are 21 years and above is greater than 26.1

A type 1 error is committed if the null hypothesis is incorrectly rejected ; this means we will be concluding that customers who are 21 years and older have higher average Consumption when they actually do not. This may lead to a restriction on beer consumption in the city when there actually isn't a need for it.

For type 2 error, a false null is incorrectly accepted, in this scenario, we are saying that the consumption of beer and cider is not beyond the mean value when in actual sense it is.

Given the set of vectors , decide which of the following statements is true:
A: Set is linearly independent and spans ℛ 3. Set is a basis for ℛ 3.
B: Set is linearly independent but does not span ℛ 3. Set is not a basis for ℛ 3.
C: Set spans ℛ 3 but is not linearly independent. Set is not a basis for ℛ 3.
D: Set is not linearly independent and does not span ℛ 3. Set is not a basis for ℛ 3.

(1,0,0),(0,1,2)

Answers

I think the answer is c sorry if I get it wrong

Tony wants to save 10,000 in 6 years. Assuming interest rate what is the minimum he must save month to goal?

Answers

Answer:

Tony wants to save $10000 in 6 years. which is approx $123. Hence final answer is C) $123.

Answer:

c

Step-by-step explanation:

We have been given that Tony wants to save $10000 in 6 years.

That means future value S = $10000

Time t= 6 years

Interest rate = 4% yearly = 0.04 yearly

n=12 months per year

Now we have to find monthly payment to recieve $10000 in 6 years. so we need to apply monthly payment formula which is

which is approx $123.

Hence final answer is C) $123.

If F(x)= 3x-2 and G(x)= x^2+8, what is G(F(x))?

Answers

Answer:

(3x-2)^2+8= 9x^2-12x+12

identify the 3D shape

Answers

Answer and Step-by-step explanation:

The 3D shape shown is a rectangle. This is the net-form of a rectangle.

#teamtrees #PAW (Plant And Water)

Answer:

rectangular prism

Step-by-step explanation:

a rectangle is not 3d. a rectangle is 2d. the correct answer is a rectangular prism.

Hi if you have a 65% grade can a 80% bring it up to a C 70%

Answers

Yes it should bring it up to a C or maybe it will be a 70 or 75

Answer:

Not a 70%, but a 72.5% (or a 73%)

Step-by-step explanation:

Assuming that the 65% is the first grade and the 80% is your second, adding both numbers and dividing by 2 will get you 72.5%.

The best possible grade you can get from that 65% is an 82.5%, or 83% if you round the grade up. 100+65=165÷2 will get you 82.5.

Select all that apply.
Which of the following name a line segment in the drawing?

Answers

Answer:

lineAF, CE, EF

Step-by-step explanation:

Because a line does not curve. And AB curves.

Assuming I got the correct question, this is the answer.

So, take this as an advice, and next time u post such questions, give a pick, so we know which question u are talking about

Thank You

Hope u understood

Please mark as brainliest

Let m Z1=(3x)º, m 22=(5x-7)", m 23=(4x+15), and m ZAFD=128º. Find m44 and m ZBFD.​

Answers

Answer:

m<4 = 52°

m<BFD = 98°

Step-by-step explanation:

m<1 = (3x)°

m<2 = (5x - 7)°

m<3 = (4x + 15)°

m<AFD = 128°

✔️Find m<4:

m<4 = 180° - m<AFD (angles on a straight line)

Substitute

m<4 = 180° - 128°

m<4 = 52°

✔️m<BFD = m<2 + m<3

Substitute

m<BFD = (5x - 7)° + (4x + 15)°

We need to find the value of x.

Create an equation to find x.

m<1 + m<2 + m<3 = m<AFD (angle addition postulate)

Substitute

3x + 5x - 7 + 4x + 15 = 128°

Add like terms and solve for x

12x + 8 = 128

12x + 8 - 8 = 128 - 8

12x = 120

12x/12 = 120/12

x = 10

m<BFD = (5x - 7)° + (4x + 15)°

Plug in the value of x

m<BFD = 5(10) - 7 + 4(10) + 15

m<BFD = 50 - 7 + 40 + 15

m<BFD = 98°

Question 1 of 10
Simplify this algebraic expression completely.
5y-3(y + 2)

Answers

Answer:

2y -6

Step-by-step explanation:

5y-3(y + 2)

Distribute

5y -3y - 6

Combine like terms

2y -6

Find the value for the side marked below.
Round your answer to the nearest tenth.
47
у
74°
y = [?]

Answers

Answer:

y ≈ 13.5

Step-by-step explanation:

In the given right triangle we have to find the measure of unknown side 'y'.

Since, measure of opposite side and adjacent side of the angle measuring 74° have been given,

We will use tangent ratio for the given angle.

tan(74°) = [tex]\frac{\text{Measure of opposite side}}{\text{Measure of adjacent side}}[/tex]

tan(74°) = [tex]\frac{47}{y}[/tex]

y = [tex]\frac{47}{\text{tan}(74^{\circ})}[/tex]

y = 13.48

y ≈ 13.5 units

Your job in a company is to fill quart sized bottles of oil from a full 50-gallon oil drum

Answers

Step-by-step explanation:

....

I Dont Known........

Answer:

16 full cases

Step-by-step explanation:

4 quarts to a gallon

50 gallons is 200 quarts (50 x 4)

200 quarts / 12 quarts per case = 16.66667 (.66667 isn't a full case)

so, it's 16

Translate the phrase into an algebraic expression.
3 more than b

Answers

Answer:

b+3 or 3+b

Step-by-step explanation:

Helen is taking part in a quiz on tv. The Probability she answers the questions correctly is 4/5. Helen is asked two questions. Calculate the probability she answered both questions correctly

Answers

Answer:

16/25

Step-by-step explanation:

To find the probability that she gets both questions right, multiply the probabilities together:

4/5 x 4/5

= 16/25

So, the probability that she answers both correctly is 16/25

2,45,250 students appeared for an entrance examination. If 94,750 students did not get admission, find how many students got admission.





can i please get the answer

Answers

Answer:

2.45.250- 94.750

= 92. 2975. this is the learners who got the admission

Answer:

1,50,500 students

Step-by-step explanation:

Hope this helps... vote as brainliest

What is the axis of symmetry for the function f(x)=7−4x+x2?

x = –3
x = –2
x = 2
x = 3

Answers

Answer:

x = 2

Step-by-step explanation:

[tex]y = {x}^{2} - 4x + 7 \\ y = (x - 2) {}^{2} - 4 + 7 \\ y = {(x - 2)}^{2} + 3[/tex]

Therefore, axis of symmetry is x = 2

The solution is: x=2, is the axis of symmetry for the function f(x)=7−4x+x2.

What is function?

Function, in mathematics, an expression, rule, or law that defines a relationship between one variable (the independent variable) and another variable.

Here, we have,

f(x)=7−4x+x^2

Rewriting as

f(x)  = x^2 -4x+7

a =1  b -4  c=7

The axis of symmetry is:

h = -b/2a

 = -(-4)/ 2(1)

 = 4/2(1)

 = 4/2  

 =a

The axis of symmetry is x=2.

Hence, The solution is: x=2, is the axis of symmetry for the function f(x)=7−4x+x2.

To learn more on function click:

brainly.com/question/21145944

#SPJ7

Stevens College plans to have 20 computers for every 100 students. How many computers are needed for 1,500 students?

Answers

Answer:

300 computers

Step-by-step explanation:

So I divided 1500 out of a 100 and got 15, then I multiply 15 to 20 and got 300.

(I am a high schooler so I hope this is 3rd grade math because I notice you are a college student and I hope this not some college tricky math, if you get this wrong I am truly sorry)

Ahmad made $114 for 12 hours of work. At the same rate, how many hours would he have to work to make $108?​

Answers

Answer:6

Step-by-step explanation:


Answer: 6

Step-by-step explanation

What is the standard form of y - 8 = 2(x + 3)

Answers

Answer:

y=2x+14

Step-by-step explanation:

y=2x+2.3+8=2x+14

1, Find the interior angle of a regular polygon with 20 sides. What is the size of exterior angle?
2, Calculate the
(I) exterior angle
(ii) the number of sides of a regular polygon with an interior angle of
(a) 60° (b) 72° (c) 165°​

Answers

Answer:

Step-by-step explanation:

1) (20 -2) * 180 = 3240 (sum of the inner angles)

3240 : 20 = 162 degrees

2)  (I) 180 - 162 = 18 degrees

(ii)

a = 3 (it is an equilateral triangle)

b = 5 (it is a pentagon)

c = 24

Answer:

1. 180(n-2) gives you the angle sum

devide by n to get the value of one interior angle

n are the number of sides, or corners

180(20-2)/20 = 162° is the interior angle.

the exterior angle is just 360°-162° = 198°

2i) seems to be included in 1), pls clarify if that's not the case.

remember

180(n-2)/n = int.angle

let's do this with (a) 60°

180(n-2)/n = 60

(180n-360)/n = 60 |*n

180n-360 = 60n |-180n

-360 = -120n |/(-120)

3 = n

2iia) 3 sides / triangle

2iib) 5 sides / pentagon

2iic) 24 sides

calculate the value of A in the statement​

Answers

please edit your question man

I WILL MAKE YOUR ANSWER THE BRAINLIST MAKE SURE YOU ARE RIGHT

FIND THE VOLUME OF THE CONE

Answers

Answer:

301.59

Step-by-step explanation:

V=1/3hπr²

sorry in advance if its wrong, this is my 1st time answering this type of question. that's what i got for the answer

plz answer this very important​

Answers

Answer:

16

Step-by-step explanation:

From the question given above, the following data were obtained:

1 = 1

2 = 4

3 = 9

4 =?

Observing the data, we can see that the numbers on the right side are simple the squares of the numbers on the left side. This is illustrated below:

1 = 1² = 1

2 = 2² = 4

3 = 3² = 9

Thus, we shall use the same logic to obtain that of 4. This is illustrated below:

4 = 4² = 16

Thus the answer to the question is 16.

A certain game consists of rolling a single fair die and pays off as follows: $10 for a 6, $7 for a 5, $4 for a 4, and no payoff otherwise,
Find the expected winnings for this game.
The expected winnings for this game are
(Round to the nearest hundredth.)
1
m
21
m
se
?
Enter your answer in the answer box.

Answers

Answer:

$3.50

Step-by-step explanation:

Given:

$10 for a 6, $7 for a 5, $4 for a 4, and no payoff otherwise

P(6) = 1/6 ; p(5) = 1/6 ; p(4) = 1/6 ; p(1,2or3) = 3/6 = 1/2

P(x) ____ 1/6 _____ 1/6 _____1/6 _____1/2

x______ 10 _______ 7 _____ 4 _______ 0

Expectwd value ; E(x)

Σx*p(x) = (1/6 * 10) + (1/6 * 7) + (1/6 * 4) + (1/2 * 0)

E(x) = 3.50

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