In a study of reaction times to a specific stimulus, a psychologist recorded these data (in seconds). Find the variance and standard deviation. Use a TI-83 Plus/TI-84 Plus calculator and round the answers to at least two decimal places.

Answers

Answer 1

Answer:

s² = 0.7965

s = 0.8925

Step-by-step explanation:

Given the data :

Class limit __ midpoint(x) ___ Frequency

2.1 - 2.7 ______2.4 ________13

2.8 - 3.4 ______3.2 _______ 14

3.5 - 4.1 ______ 3.8 _______ 10

4.2 - 4.8 ______4.5 _______ 6

4.9 - 5.5______ 5.2 ________2

5.6 - 6.2______ 5.9 ________ 1

The midpoint was calculated thus :

(Upper limit + lower limit) / 2

Using a graphing calculator :

The sample variance, s² = 0.7965

The sample standard deviation, s = 0.8925


Related Questions

Please please help need today

Answers

Answer:

you need to zoom in i cant see plz :)

Step-by-step explanation:

I got b
I did 200+5% which equal to 210
Hope this is correct sorry if not

Savannah hike 1 mile every day after Hiking on Monday she has height 102 miles after hiking on Friday how many miles will she have hike

Answers

Answer:

106

Step-by-step explanation:    ts 6 9 21  30

After Monday

    102 + Tuesday + Wednesday + Thursday + Friday         After

    102 +       1        +        1             +        1        +      1       =       106

A salesperson at a jewelry store earns 4​% commission each week. Last​ week, Heidi sold $680 worth of jewelry. How much did make in​ commission? How much did the jewelry store make from ​sales?

Answers

Answer:

$27.2

Step-by-step explanation:

680x0.04=. 27.2

She made $27.2 last week

Write the recurring decimal 0.48 a
as a fraction.
Show all your working.

Answers

Answer:

[tex] \frac{16}{33} [/tex]

Step-by-step explanation:

[tex]x = 0.48... \\ 100 \times x = 0.48 \times 100 \\ 100x - x = 48.48.. - 0.48 \\ 99x = 48 \\ \frac{99x}{99} = \frac{48}{99} \\ x = \frac{16}{33} [/tex]

Consider a test of H 0: μ = 85 performed with the computer. SPSS reports a two-tailed p-value of 0.2714. Make the appropriate conclusion for the given situation: H a: μ > 85, z = 1.10, α = 0.10

Answers

Answer:

p-value of 0.1357 > 0.1, which means that we do not reject the null hypothesis, that is, there is not sufficient evidence to conclude that the population mean is above 85.

Step-by-step explanation:

Decision:

If the p-value is greater than the significance level, we accept the null hypothesis. Otherwise, we reject the null hypothesis.

In this question:

Null hypothesis:

μ = 85

Alternate hypothesis:

a: μ > 85

SPSS reports a two-tailed p-value of 0.2714.

We are testing if the mean is greater than a value, which is a one-tailed test, so the p-value is of 0.2714/2 = 0.1357

Decision:

p-value of 0.1357 > 0.1, which means that we do not reject the null hypothesis, that is, there is not sufficient evidence to conclude that the population mean is above 85.

A bug starts at position (-3, -3) on the floor. It crawls along the vector (2, 6). What is the the final position of the bug on the floor? How far and in what direction did it crawl to get there?

Answers

Step-by-step explanation:

the final position = (-3+2 , -3+6) => (-1, 3)

the distance from the origin point =

√(2²+6²) = √(4+36) = √40 units or 6.3 units

the direction = tan~¹ 6/2 = 71.6°

solving quadratic equation using the completing the square method. (a).x²+20x-12=0​

Answers

Answer:

[tex]x = -10 + 4 \sqrt7 \ , \ x = -10 - 4 \sqrt7[/tex]

Step-by-step explanation:

x²+20x-12=0

a = 1, b = 20, c = -12

[tex]x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2x}[/tex]

[tex]x = \frac{-20 \pm \sqrt{448}}{2}\\\\x = \frac{-20 \pm \sqrt{8 \times 8 \times 7}}{2}\\\\x = \frac{-20 + 8\sqrt{7}}{2} \ , \ x = \frac{-20 - 8 \sqrt7}{2}\\\\x = \frac{-10 + 4\sqrt{7}}{1} \ , \ x = \frac{-10 - 4 \sqrt7}{1}\\\\x = -10 + 4 \sqrt7 \ , \ x = -10 - 4 \sqrt7[/tex]

Write the percent of the figure that is shaded.

PLEASE HELP ILL GIVE EXTRA POINTS!!!

Answers

Answer:

so the total is 20 and its at ten so

10/20=5/10=1/2

so 50 percent

plzzz brainlest

50%

Half of the number line is shaded, which means that 50% of the number line is shaded.

Have a nice day

Use the graph of f(x) to estimate f(3).

Answers

Answer:

f(3) = -8

Step-by-step explanation:

f(3) means find the y value when x=3

Using the graph the y value when x =3 is -8

f(3) = -8

what is butterfly cycle​

Answers

The butterfly and moth develop through a process called metamorphosis. This is a Greek word that means transformation or change in shape. There are four stages in the metamorphosis of butterflies and moths: egg, larva, pupa, and adult.

mark me brainliesttt :)))

Siobhan needs to fill her cylindrical shaped fish tank. The base of the fish tank has a diameter of 10 in, and the height of the fish tank is 8 in. Which statement describes how Siobhan can find out how much water she needs to fill the fish tank

Answers

Answer:

C = 5^2 * Pi * 8

Step-by-step explanation:

Formula = [tex]r^{2}[/tex]*Pi*h

r = d / 2

d=10, so r=5

h = 8

I really need help or I’m gonna fail the semester

Answers

Rational Number, Real Number

Find the first two expressions in the sequence _, _, 4x+5, 5x+7, 6x+9, 7x+11, 8x+13...

Answers

Answer:

First term: 2x+1

Second term: 3x+3

Step-by-step explanation:

The coefficient of x is going up by 1 time each time while the constant term is going up by 2.

We are looking at these two questions basically:

1) What are the first two terms in?

_,_,4,5,6,7,8

2) What are the first two terms in?

_,_,5,7,9,11,13

Answers:

1) Since the sequence is going up by 1 reading left to right, then right to left it's going down by 1.

So before 4, we have 3.

Before 3, we have 2.

The sequence for the coefficient of x is 2,3,4,5,6,7,8

2) Since the sequence is going up by 2 from left to right, then it's going down by 2 reading right to left.

So before 5, we have 3.

Before 3, we have 1.

The sequence for the constant term is 1,3,5,7,9,11,13.

So first two terms of the sequence in ascending order according to the sequence is:

2x+1

3x+3

I need the answer plzzzzzz

Answers

Answer:

D

Step-by-step explanation:

compare the numbers

Write the slope-intercept form of the equation for the line.

Answers

Answer:

its 4/2 or simplified to 2/1

Step-by-step explanation:

mark me brainliest pls

I HAVE ONE WEEK OF SCHOOL CAN SOMEONE HELP?!

Answers

9514 1404 393

Answer:

  1. 5 seconds

  2. 4.5 seconds

Step-by-step explanation:

Both of these questions can be solved the same way. Each quadratic gives height as a function of time. You're interested in the time at which the height is zero. Factor the quadratic and find the positive value of x that makes the relevant factor be zero.

__

1) y = -15x(x -5)

  x = 5 makes the second factor zero

The golf ball is in the air 5 seconds.

__

2) y = -12x(x -4.5)

  x = 4.5 makes the second factor zero

The football is in the air for 4.5 seconds.

_____

Additional comment

The "zero product rule" tells you a product will be zero if and only if one or more of the factors is zero. When a factored quadratic (or any other polynomial) is zero, one of the factors must be zero. If the factor is of the form (ax+b), then the corresponding solution is ...

  ax+b = 0   ⇒   ax = -b   ⇒   x = -b/a

That is, once you have the factored form, you can write the solutions "by inspection."

A submarine sits at –300 meters in relation to sea level. Then it descends 115 meters. What is its new position in relation to sea level?

Answers

Answer:

-415 meters

Step-by-step explanation:

As it was already -300 and it decended even more

so:

-300-`115=-415

Answer:

The answer is A, -415 meters.

Step-by-step explanation:

All right, so the key words we need here are -300, descends, and 115.

Descends means go lower, or in this case, subtract.

We are already at -300 and we descend 115, so we are going to subtract.

Subtracting a number is the same as adding the negative of that number.

-300 + -115 = -415

The answer is A, -415 meters.

Hope this helps, please mark brainliest if possible. :)

The total cost
of an $82 meal
with a 20% tip

Answers

Answer:

$16.40

Step-by-step explanation:

Answer:

98.40

Step-by-step explanation:

First find the tip

82* 20%

82* .20

16.40

Add the tip to the cost of the mean

82+16.40

98.40

which choices is equivalent to the product below ? 2.3.6

Answers

Answer:

What product

Step-by-step explanation:

A certain electronics manufacturer found that the average cost C to produce x DVD/Blu- ray players can be found using the equation C = 0.04 x 2 − 5 x + 900 . What is the minimum average cost per machine and how many DVD/Blu-ray players should be built in order to acheive that minimum?
The minimum average cost is ?
The number of DVD/Blu-ray players that should be build to acheive the minimum is?

Answers

Answer:

Minimum average cost = 743.75

Number of dvds to achieve the cost = 62.5

Step-by-step explanation:

Given the cost equation

C = 0.04x² − 5x + 900

To Obtian the minimum average cost ;

Find dc/dx = 0

Diffentiate cost, c it ith respect to x

dc/dx = 2(0.04x) - 5

dc/dx = 0.08x - 5 = 0

0.08x = 5

x = 5 / 0.08

x = 62.5

Substitute the value of x into C to obtain the minimum average cost

C = 0.04(62.5)² - 5(62.5) + 900

C = 743.75

The point (3,−4) lies on the graph of y=(x−5)2+k where k is some constant. Which other point must also lie on the same graph?

Answers

Answer:

The other point lies on the graph is (0, - 8).

Step-by-step explanation:

Point (3, - 4) lies on the graph [tex]y = (x -5)^2 + K[/tex]

So, put x = 3 and y = - 4 in the equation.

[tex]- 4 = ( 3 -5)^2 + K\\\\- 4 = 4 + K \\\\K= - 8[/tex]

So, the equation of graph is

[tex]y = (x - 5)^2 -8[/tex]

Let x = 5 lies on the graph so

[tex]y = (5 -5)^2 -8 \\\\y = -8[/tex]

So, the other point lies on the graph is (0, - 8).

hey besties, I need help

Answers

Answer:

C

Step-by-step explanation:

[tex]\frac{2}{3} (x + 2) - \frac{1}{3} (x - 2)[/tex]

First, multiply [tex]\frac{2}{3}[/tex] to [tex](x + 2)[/tex] , then [tex]\frac{1}{3}[/tex] to [tex](x - 2)[/tex], after you have done that, you would get an equation looking like this[tex]\\[/tex]:

[tex]\frac{2}{3} x + \frac{4}{3} - \frac{1}{3}x - \frac{2}{3}[/tex]

Next, add and/or subtract the fractions with the variables together and the ones without together, and that is how you get to your final answer

[tex]\frac{1}{3}x + \frac{2}{3}[/tex]

Please help me with my math answer

Answers

Step-by-step explanation:

20 ml is your answer

i hope it helps u

Answer:

If I'm reading it correctly the answer should be 20.

To get that answer all you do is 4x5.

write an expression to represent multiplying twice the difference of 9 and 7 PLS HELP TYSM ASAP TOO PLS

Answers

Answer:

2*3

Step-by-step explanation:

multiplying 2 the difference subtraction of 9-7 your answer is  2*3

Josh buys candy that costs $8 per pound. He will spend at most $88 on candy. What are the possible numbers of pounds he will buy?

Answers

Answer:

11 pounds

Step-by-step explanation:

You would do 88 divided by 8 to get 11

What is the value of the upper quartile?

Answers

i believe the answer is 6

Leticia invests $200 at 5% interest. If y represents the amount of money after x time periods, which describes the graph of the exponential function relating time and money?

The initial value of the graph is 200. The graph increases by a factor of 1.05 per 1 unit increase in time.
The initial value of the graph is 200. The graph increases by a factor of 5 per 1 unit increase in time.
The initial value of the graph is 500. The graph increases by a factor of 2 per 1 unit increase in time.
The initial value of the graph is 500. The graph increases by a factor of 1.02 per 1 unit increase in time.

Answers

Answer:

First you need to state the equation that represents the function.

Investment is $200 and interest rate is 5%, y is the amount of money after x periods.

Note that after 1 period the amount of money is 200 plus 5% interest, which is 200 + 5%(200) = 200 (1 +5%) = 200 (1 + 0.05) = 200 (1.05)

After 2 periods the amount is 200(1.05)*(1.05) = 200 (1.05)^2

After 3 periods the amount is 200 (1.05)^3

And now you can deduce that after x periods y = 200 (1.05)^x

You can then analyze the function to predict the shape and critical points of the graph.

The answers are based in the initial value and the increasing factor.

The initial value is when x = 0, which yields to y = 200 (1.05)^0 = 200*1 = 200

And the increasing factor is 1.05 because any value is the previos one times 1.05.

Step-by-step explanation:

The graph shows 200. And the factor down

Which figure has at least one line of symmetry?

Answers

Answer:

the second green shape because the first one is a rectangle which has 2 equal sides

Answer:

the third orange one

Step-by-step explanation:

i have the same question and these 2 show up as answers on both so it has to be this one

In ΔVWX, the measure of ∠X=90°, XW = 65, WV = 97, and VX = 72. What is the value of the cosine of ∠V to the nearest hundredth?

Answers

Answer:

The cosine of ∠V is of 0.74.

Step-by-step explanation:

Relations in a right triangle:

The cosine of an angle is given by the length of the adjacent side divided by the length of the hypotenuse.

XW = 65, WV = 97, and VX = 72.

[tex]\sqrt{65^2+72^2} = 97[/tex], and thus, this is a right triangle.

What is the value of the cosine of ∠V to the nearest hundredth?

The hypotenuse is the largest side, that is, WV = 97.

The adjacent side of angle V is VX = 72. So

[tex]\cos{B} = \frac{72}{97} = 0.74[/tex]

The cosine of ∠V is of 0.74.

Need help ASAP! Giving Brainliest!

Answers

ok thats cool ig what do you need help with

Answer:

A

Step-by-step explanation:

Have a nice day :)

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