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fenix001 [56]
3 years ago
9

Supposethat z is a normally distributed variable with variance 4. You collect a sample of size n for which you get a sample aver

age value of 3. You are asked to test the null hypothesis that the mean is smaller than 2. Find the sample size n above which you can reject the null hypothesiswith a 95% of confidence.
Mathematics
1 answer:
Nikitich [7]3 years ago
7 0

Answer:

The sample size is 4

Step-by-step explanation:

Null hypothesis: The mean is 2

Alternate hypothesis: The mean is less than 2

Mean = 3

sd = sqrt(variance) = sqrt(4) = 2

At 95% confidence level, t-value is 1.960

Assuming the lower bound of the mean is 1.04

Lower bound = mean - (t×sd/√n)

1.04 = 3 - (1.96×2/√n)

3.92/√n = 3 - 1.04

3.92/√n = 1.96

√n = 3.92/1.96

√n = 2

n = 2^2

n = 4

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The radius of a sphere is 3 inches. Which represents the volume of the sphere?
Mrac [35]

Answer:

b

Step-by-step explanation:

The volume (V) of a sphere is calculated as

V = \frac{4}{3}πr³ ( where r is the radius )

Here r = 3, thus

V = \frac{4}{3}π × 3³

   = \frac{4}{3}π × 27 = 4π × 9 = 36π in³ → b

3 0
3 years ago
Read 2 more answers
Use the discriminant to describe the roots of each equation. Then select the best description.
Paha777 [63]

The <em>quadratic</em> equation 3 · x² + 7 · x - 2 = 0 has a <em>positive</em> discriminant. Thus, the expression has two <em>distinct real</em> roots (<em>real</em> and <em>irrational</em> roots).

<h3>How to determine the characteristics of the roots of a quadratic equation by discriminant</h3>

Herein we have a <em>quadratic</em> equation of the form a · x² + b · x + c = 0, whose discriminant is:

d = b² - 4 · a · c     (1)

There are three possibilities:

  1. d < 0 - <em>conjugated complex</em> roots.
  2. d = 0 - <em>equal real</em> roots (real and rational root).
  3. d > 0 - <em>different real</em> roots (real and irrational root).

If we know that a = 3, b = 7 and c = - 2, then the discriminant is:

d = 7² - 4 · (3) · (- 2)

d = 49 + 24

d = 73

The <em>quadratic</em> equation 3 · x² + 7 · x - 2 = 0 has a <em>positive</em> discriminant. Thus, the expression has two <em>distinct real</em> roots (<em>real</em> and <em>irrational</em> roots).

To learn more on quadratic equations: brainly.com/question/2263981

#SPJ1

7 0
2 years ago
The sum of 5 consecutive integers is 505 what is the third number in the sequence
saw5 [17]
5 consecutive integers : x, x + 1, x + 2, x + 3, x + 4

x + x + 1 + x + 2 + x + 3 + x + 4 = 505
5x + 10 = 505
5x = 505 - 10
5x = 495
x = 495/5
x = 99

x + 1 = 99 + 1 = 100
x + 2 = 99 + 2 = 101 <=== 3rd number is 101
x + 3 = 99 + 3 = 102
x + 4 = 99 + 4 = 103
3 0
3 years ago
HELP PLEASE i just need the answer and if you could tell me how you did it I WILL GIVE 50 POINTS ​
lidiya [134]

Answer:

G 36

Step-by-step explanation:

Hope this helps. Pls give brainliest.

8 0
3 years ago
Here's what Gabriel and Kayla actually wrote.
stiv31 [10]
When 2 or more expressions are equivalent, that means they have the same outcome or result.
5 0
3 years ago
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