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aev [14]
3 years ago
15

A random sample of 25 statistics examinations was selected. The average score in the sample was 76 with a variance of 144. Assum

ing the scores are normally distributed, the 99% confidence interval for the population average examination score is _____. a. 70.02 to 81.98 b. 69.82 to 82.18 c. 69.29 to 82.71 d. 70.06 to 81.94
Mathematics
1 answer:
ki77a [65]3 years ago
4 0

Answer:

The confidence interval is from 69.82 o 82.18

Step-by-step explanation:

Using this formula X ± Z (s/√n)

Where

X = 76 --------------------------Mean

S = Standard Deviation

If Variance = 144

S = √144

S = 12

n = 25 ----------------------------------Number of observation

Z = 2.576 ------------------------------The chosen Z-value from the confidence table below

Confidence Interval || Z

80%. || 1.282

85% || 1.440

90%. || 1.645

95%. || 1.960

99%. || 2.576

99.5%. || 2.807

99.9%. || 3.291

Substituting these values in the formula

Confidence Interval (CI) = 76 ± 2.576 (12/√25)

CI = 76 ± 2.576(12/5)

CI = 76 ± 2.576(2.4)

CI = 76 ± 6.1824

CI = 76 + 6.1824 ~ 76 - 6.1824

CI = 82.1824 ~ 69.8176

CI = 82.18 ~ 69.82

In other words the confidence interval is from 69.8176 to 82.1824

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soldi70 [24.7K]

Answer:

1

Step-by-step explanation:

Given the system of equations below

y=2x+5

y=x+6

Equating the right hand side of the expressions we will have;

2x+5 = x+6

Collect the like terms;

2x - x = 6 - 5

x = 1

Hence the x-coordinate of the solution to the system is 1

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4 0
3 years ago
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Look at this equation <br> y=7x+1/3x-6<br> if 3x=15, then what is the value of y?
Anarel [89]

Answer:

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Step-by-step explanation:

3x=15: x=5

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3 years ago
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I need help please?
Natali [406]

The Outcome of event A and B is simply the intersection of both sets written as A ∩ B is; C: {seagull, crow}

<h3>How to write sets notation?</h3>

From the image, we are given the animals namely; Pig, Penguin, Seagull, Tiger, Crow, Bat, Mosquito.

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Now, we are told that;

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Triangles A and B apears not to be congruent to any others triangles.

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