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AleksAgata [21]
2 years ago
11

Suppose that a standardized biology exam has a mean score of 80% correct, with a standard deviation of 3. The school administrat

ion believes that the new class of freshmen have a different mean exam score. A sample of 65 students from the freshmen class is used and a mean score of 76% correct is obtained.
Calculate a 99% confidence interval. List the lower bound (rounded to 2 decimal places) and the upper bound (rounded to 2 decimal places).
Mathematics
1 answer:
NemiM [27]2 years ago
6 0

Answer:

The 99% confidence interval is between 62.36%(lower bound) and 89.64%(upper bound).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of \pi, and a confidence level of 1-\alpha, we have the following confidence interval of proportions.

\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}

In which

z is the zscore that has a pvalue of 1 - \frac{\alpha}{2}.

A sample of 65 students from the freshmen class is used and a mean score of 76% correct is obtained.

This means that n = 65, \pi = 0.76

99% confidence level

So \alpha = 0.005, z is the value of Z that has a pvalue of 1 - \frac{0.005}{2} = 0.995, so Z = 2.575.

The lower limit of this interval is:

\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.76 - 2.575\sqrt{\frac{0.76*0.24}{65}} = 0.6236

The upper limit of this interval is:

\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.76 + 2.575\sqrt{\frac{0.76*0.24}{65}} = 0.8964

0.6236*100 = 62.36%

0.8964*100 = 89.64%

The 99% confidence interval is between 62.36%(lower bound) and 89.64%(upper bound).

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Answer:

x \: is \: not \: a \: solution \: in \to \: 5x + 4 < 19. \\

Step-by-step explanation:

\: if \: x = 3 \: then \\  4x-1=2x +5  \: is \: same \: as  \to \:  \\ 4(3) - 1  = 2(3) + 5\\ 12 - 1 = 6 + 5 \\ 11 =11 \to \: \\  \boxed{ x \: is \:a \:  solution \: here}  \\  \\ if \: x = 3 \\ then \to \\ 5x + 4    <   19\: is \: same \:as \to \\ 5(3) + 4 < 19 \\ 15 + 4 < 19 \\ 19 \: is \: equal \: to \: 19 : \\ 19 \:  can \: not \: be \: less \: than \: 19 \\ \boxed{ henc e\: x \: is \: not \: a \: solution \: here}

♨Rage♨

6 0
3 years ago
The table represents the average daily price of a two-bedroom beachfront condo each month, with January represented as month 1,
ruslelena [56]

Answer:

y = - 9.1768x2 + 122.2567x + 14.9091

Step-by-step explanation:

Given the following :

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Using the online regression equation graphing tool ; The quadratic model obtained in the form,

y = Ax^2 + Bx + C is :

y = - 9.1768x2 + 122.2567x + 14.9091

Attached below is a picture of the quadratic regression curve.

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What is the y-intercept of the line with a slope of − 1/4 that passes through the point (−2, −9/2 )?
svlad2 [7]
-9/2 = -1/4(-2)+ b

-9/2 = 1/2 + b
Minus 1/2 over

B= -5

Hope this helps!
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3 years ago
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3 minutes

Step-by-step explanation:

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2 years ago
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Give the values of a, b, and c needed to write the equation's general form.<br>1/4x^2+5=0
Firdavs [7]

●✴︎✴︎✴︎✴︎✴︎✴︎✴︎✴︎❀✴︎✴︎✴︎✴︎✴︎✴︎✴︎✴︎✴︎●

   Hi my lil bunny!

❧⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯☙

Let's solve your equation step-by-step.

\frac{1}{4} x^2+5=0

For this equation: a=0.25, b=0, c=5

0.25x^2 + 0x + 5 = 0

Step 1: Use quadratic formula with a=0.25, b=0, c=5.

x = \frac{-b ± \sqrt{b^2 - 4ac} }{2a}

x = \frac{-(0) ± \sqrt{(0)^2 -4 (0.25) (5)  } }{2(0.25)}

x = \frac{0 ± \sqrt{-5} }{0.5}

Answer : No Real Solutions.

❧⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯☙

●✴︎✴︎✴︎✴︎✴︎✴︎✴︎✴︎❀✴︎✴︎✴︎✴︎✴︎✴︎✴︎✴︎✴︎●

If this helped you, could you maybe give brainliest..?

Also Have a great day/night!

❀*May*❀

5 0
3 years ago
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