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leonid [27]
4 years ago
15

Suppose a statistics instructor believes that there is no significant difference between the mean class scores of statistics day

students on Exam 2 and statistics night students on Exam 2. She takes random samples from each of the populations. The mean and standard deviation for 35 statistics day students were 75.86 and 16.91.The mean and standard deviation for 37 statistics night students were 75.41 and 19.73. The day" subscript refers to the statistics day students. The "night subscript refers to the statistics night students. Assume that the standard deviations are equal. A concluding statement is:
a. There is sufficient evidence to conclude that statistics night students' mean on Exam 2 is better than the statistics day students' mean on Exam 2.
b. There is insufficient evidence to conclude that the statistics day students' mean on Exam 2 is better than the statistics night students' mean on Exam 2.
c. There is insufficient evidence to conclude that there is a significant difference between the means of the statistics day students and night students on Exam 2
d. There is sufficient evidence to conclude that there is a significant difference between the means of the statistics day students and night students on Exam 2
Mathematics
1 answer:
zhuklara [117]4 years ago
5 0

Answer:

c. There is insufficient evidence to conclude that there is a significant difference between the means of the statistics day students and night students on Exam 2

Step-by-step explanation:

Given that a  statistics instructor believes that there is no significant difference between the mean class scores of statistics day students on Exam 2 and statistics night students on Exam 2.

Group   Group One     Group Two  

Mean 75.8600 75.4100

SD 16.9100 19.7300

SEM 2.8583 3.2436

N 35       37      

*SEM is std error/sqrt n

Mean difference = 0.4500

H_0: \bar x = \bar y\\H_a: \bar x \neq \bar y

(two tailed test)

Std error for difference = 4.342

Test statistic t = \frac{0.45}{4.342} \\=0.1036

df =70

p value = 0.9178

Since p >0.05 we accept H0

c. There is insufficient evidence to conclude that there is a significant difference between the means of the statistics day students and night students on Exam 2

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Lena [83]

Answer:

T.A. = 144 + 36√3 units²

Step-by-step explanation:

∵ The total surface area of the pyramid = the sum of the area of

   the four  faces (one base and 3 side faces)

∵ The 3 side faces have the same dimensions 12 , 10 , 10

∴ the area of the 3 faces = 3 × 1/2 × 12 × h

∵ The height of each triangle is ⊥ to its base

∵ The triangle are isosceles

∴ The height bisects the base

∴ h² = 10² - 6² = 64

∴ h = √64 = 8

∴ The area of the 3 triangles = 3 × 1/2 × 12 × 8 = 144 units²

∵ The base is equilateral Δ with side length 12

∵ Area equilateral triangle = 1/4 × s² × √3

∴ The area of the base = 1/4 × (12)² × √3 = 36√3 units²

∴ T.A. = 144 + 36√3 units²

7 0
3 years ago
In a survey of women in a certain country the mean height was 62.9 inches with a standard deviation of 2.81 inches answer the fo
Natasha2012 [34]

The question is incomplete. The complete question is :

In a survey of women in a certain country ( ages 20-29), the mean height was 62.9 inches with a standard deviation of 2.81 inches.  Answer the following questions about the specified normal distribution.  (a) What height represents the 99th percentile?  (b) What height represents the first quartile?  (Round to two decimal places as needed)

Solution :

Let the random variable X represents the height of women in a country.

Given :

X is normal with mean, μ = 62.9 inches and the standard deviation, σ = 2.81 inches

Let,

$Z=\frac{X - 62.9}{2.81}$ , then Z is a standard normal

a). Let the 99th percentile is = a

The point a is such that,

$P(X

$P \left( Z < \frac{a-62.9}{2.81} \right) = 0.99$

From standard table, we get : P( Z < 2.3263) =0.99

∴ $\frac{(a-62.9)}{281} = 2.3263$

  $a= (2.3263 \times 2.81 ) +62.9$

     = 6.536903 + 62.9

     = 69.436903

     = 69.5 (rounding off)

Therefore, the height represents the 99th percentile = 69.5 inches.

b). Let b = height represents the first quartile.

It is given by :

P( X < b) =0.25

$P \left( Z < \frac{(b-62.9)}{2.81} \right) = 0.25$

From the standard normal table,

P( Z < -0.6745) =0.99

∴ $\frac{(b-62.9)}{2.81}= 0.6745$

$b=(0.6745 \times 2.81) +62.9$

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Therefore, the height represents the 1st quartile is 64.8 inches.

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3 years ago
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Answer:

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Step-by-step explanation:

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therefore the probability is:

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Which means that there is a 44.4% chance of drawing a blue pair.

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Answer:

Step-by-step explanation:

Given that, .

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So, the area of the whole quilt is 600.25 in²

8 0
3 years ago
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