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iragen [17]
3 years ago
15

Approximately 54% of mathematics students do their homework on time. In a class of 250 students, what is the mean, variance, and

standard deviation if we assume normality and use the normal distribution as an approximation of the binomial distribution?
A) Mean = 135 Variance = 62 Standard Deviation = 8B) Mean = 53 Variance = 62 Standard Deviation = 8C) Mean = 54 Variance = 8 Standard Deviation = 62D) Mean = 135 Variance = 8 Standard Deviation = 62
Mathematics
1 answer:
sleet_krkn [62]3 years ago
6 0

Answer:

A) Mean = 135 Variance = 62 Standard Deviation = 8

Step-by-step explanation:

Given that :

Proportion (p) = 54%

Sample size (n) = 250

Using Normal approximation :

Mean = np

Mean = 250 * 0.54 = 135

Variance = npq ; q = 1 - p = 1 - 0.54 = 0.46

Variance = (250 * 0.54 * 0.46) = 62.1 = 62

Standard deviation = √variance = √62.1

Standard deviation = 7.8803553 = 8

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Alex787 [66]

Answer: 259/260 or 0.99615 (depending on which answer format your teacher wants)

There are 10 numbers in the set {0, 1, 2, ..., 9}. There are 26 letters in the set {A, B, C, ..., Z}. Multiply those values: 10*26 = 260. So there are 260 ways to pick a number followed by a letter. One example is 7P.

There is only one way Matthew can get the correct answer, and there are 260 - 1 = 259 ways to get the wrong answer. We divide 259 over 260 to get the probability of getting the incorrect answer, which is 259/260.

If you need this fraction in decimal form, then use a calculator to find that 259/260 = 0.99615 approximately

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2 years ago
Help me solve this equation and show work <br><br> 11d + 17b = 95 <br> d + b = 7
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Answer:

{d,b}={4,3}

Step-by-step explanation:

[1]    11d + 17b = 95

  [2]    d + b = 7

Graphic Representation of the Equations :

   17b + 11d = 95        b + d = 7  

 

Solve by Substitution :

// Solve equation [2] for the variable  b

 [2]    b = -d + 7

// Plug this in for variable  b  in equation [1]

  [1]    11d + 17•(-d +7) = 95

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// Solve equation [1] for the variable  d

  [1]    6d = 24

  [1]    d = 4

// By now we know this much :

   d = 4

   b = -d+7

// Use the  d  value to solve for  b

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Solution :

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

let us take three consecutive numbers be (x + 1), (x + 2) and (x + 3)

Now,

The sum of three consecutive integers is 90

i.e.,

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<h2><em><u>VERIFICATION</u></em><em><u>:</u></em></h2>

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28 + 1 + 28 + 2 + 28 + 3 = 90

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