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Ainat [17]
3 years ago
13

The time it takes for a statistics professor to mark a single midterm test is normally distributed with a mean of 4.8 minutes an

d a standard deviation of 2.3 minutes. There are 55 students in the professor's class. What is the probability that he needs more than 5 hours to mark all of the midterm tests?
Mathematics
1 answer:
Bess [88]3 years ago
7 0

Answer:

Step-by-step explanation:

SD of mean = 2.3/\sqrt{55} = 0.418

5 hours = 300 minutes

300 minutes/55 students = 5.45 min/student

The problem asks what is the probability he needs more than an average of 5 min/student

P(XBAR < 5.0) = P((XBAR - 4.8) / 0.418) < (5.0 - 4.8) /0.418) = P(Z < 0.478) = 0.8893        

P(XBAR > 5.0) = 1 - 0.8893 = 0.1107

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Please help. i need to pass.
FrozenT [24]
Plug 8 for y

8 = 2x + 4

Subtract 4

4 = 2x

Divide by 2

x = 2

Plug 16 for y

16 = 2x + 4

Subtract by 4

12 = 2x

Divide by 2

x = 6

Substitute 20 for y

20 = 2x + 4

16 = 2x

x = 8

Substitute 22 for y

22 = 2x + 4

18 = 2x

9 = x

So the values are 2, 6, 8, 9
5 0
3 years ago
Could some please help me with these two
damaskus [11]

Answer:

+3

Step-by-step explanation:

(-m)^(-3) = -m^3, since (-1)^-3 = 1 / (-1).

If m = 2 then we have -2^(-3), or  -1 / [2^3]), or -1/8.

Finally, if n = -24, the original expression becomes

(-1/8)(-24) = +3

Second problem:  Only the first expression simplifies to a negative result.  

4 0
3 years ago
F(x) 3x^4-4x^2-3<br> Is this function odd?
Karo-lina-s [1.5K]

Answer:

No.

Step-by-step explanation:

f(x) = 3x^4-4x^2-3

If a function is odd then  f(-x) = -f(x) for all values of x.

Here f(-x) = 3(-x)^4 - 4(-x)^2 - 3

= 3x^4 - 4x^2 - 3

So f(-x) = f(x) which makes it even.

8 0
2 years ago
What is the simplified expression for 3^3 x 3^3/ 3^4
Juli2301 [7.4K]

Answer:

9

Step-by-step explanation:

\frac{3^{6} }{3^{4} }

3^{2}

9

3 0
3 years ago
What is the estimate of 92 times 68
solong [7]
92 can be rounded to 90
68 can be rounded to 70

90 x 70 = 6300
8 0
3 years ago
Read 2 more answers
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