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Zarrin [17]
1 year ago
14

during one semester, the time elaine spent doing homework or participating in extracurricular activities was 20 percent less tha

n the time she spent attending class. if she spend a total of 981 hours attending class, doing homework, or participating in extracurricular activities, how many hours did she spend attending class?
Mathematics
1 answer:
polet [3.4K]1 year ago
7 0

Answer:

963 hours

Step-by-step explanation:

I subtracted 20 from the 981

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An important factor in selling a residential property is the number of times real estate agents show a home. A sample of 23 home
yanalaym [24]

Using the t-distribution, it is found that:

a. The <u>margin of error</u> is of 4.7 homes.

b. The 98% confidence interval for the population mean is (19.3, 28.7).

The information given in the text is:

  • Sample mean of \overline{x} = 24.
  • Sample standard deviation of s = 9.
  • Sample size of n = 23.

We are given the <u>standard deviation for the sample</u>, which is why the t-distribution is used to solve this question.

The confidence interval is:

\overline{x} \pm M

The margin of error is:

M = t\frac{s}{\sqrt{n}}

Item a:

The critical value, using a t-distribution calculator, for a two-tailed <u>98% confidence interval</u>, with 23 - 1 = <u>22 df</u>, is t = 2.508.

Then, the <em>margin of error</em> is:

M = t\frac{s}{\sqrt{n}} = 2.508\frac{9}{\sqrt{23}} = 4.7

Item b:

The interval is:

\overline{x} - M = 24 - 4.7 = 19.3

\overline{x} + M = 24 + 4.7 = 28.7

The 98% confidence interval for the population mean is (19.3, 28.7).

A similar problem is given at brainly.com/question/15180581

3 0
2 years ago
Local extreme Value for each of the Following A) F(x)=x^² - 4x² +5​
kobusy [5.1K]

Answer:

max{x²-4x²+5} = 5 at x = 0

Step-by-step explanation:

1. Find the critical numbers by finding the first derivative of f(x), set it to 0 and solve for x.

f'(x)=0

We get:

f(x) = -3x^2+5\\f'(x) = -6x\\-6x = 0\\x = 0

So the critical number is x = 0.

2. Evaluate the first derivative by plugging in the critical number and see if the derivative is positive or negative on both sides:

f'(x) is positive when the x < 0 (for example: -6*(-1)=+)

f'(x) is negative when the x > 0 (for example: -6*(1)=-)

Therefore, you have a local maximum.

Now just get the Y value by plugging in the critical number in the original function. f(0)=5

local maximum is (0,5)

4 0
2 years ago
Bill drove 715 miles in 11 hours.
Verizon [17]

Answer: It would take 7 hours.

Step-by-step explanation:

715/11 = 65

65 miles per hour

455/65 = 7

6 0
3 years ago
PLEASE HELP A store is having a sale on chocolate chips and walnuts. For 5 pounds of chocolate chips and 3 pounds of walnuts, th
Stells [14]

Answer:

Chocolate Chips cost $2.25 and Walnuts cost $3.25 per pound each

Step-by-step explanatChocion:

Let x = cost of pounds of chocolate chip cookies and y = cost of pounds of walnuts.

From the question, we get 5x+3y = 21 and 2x+6y = 24. To solve the equation, we use substitution. From the first equation, we get y = (21-5x)/3. We substitute the y into the second equation to get 2x + 6(21-5x)/3 = 24. This turns out to be 2x+(42-10x) = 24. Adding like terms you should get 42-8x = 24. Solving for x, x = $2.25 per pound. Plugging this into the first equation, we get 5(2.25)+3y = 21. Solving for y, we get $3.25 per pound of walnuts. If we plug in the numbers into the 2 equations, we will get the right total.

3 0
3 years ago
Need help thanks in advanced
olga55 [171]

Answer:-1

Step-by-step explanation:

3 0
2 years ago
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